When Analog Computers Ruled the World

Boy that reads like science fiction! This is actually a nonfiction story about my experience with a type of analog computer that was alluded to in a thesis by Mr. Richard S. Hunter and found by a scientist at Procter & Gamble who just had to have one. Actually he couldn’t have one as the crafty Mr. Hunter insisted that it would take an order of 25 to make it worth his while to set up a development project hence the machines were called the D25.

D25 (Analog Computer)

The machine was designed in 1956 and remained in production for many years, after that they were kept running with parts salvaged from retired machines. The D25 measured colors, it did this by producing a specific illumination and focusing it on the specimen then it then gathered the reflected light looking for what was missing. The missing light represents whatever the specimen absorbed. The model pictured above is from the original 25 and is said to be still working.

By analyzing the difference between the light you shine and the light you record can give you certain information that can be used to give numbers to what you can see. This is not an absolute method which is why the machine is called a color difference meter. Inside the heart of the machine was four photomultiplier tubes, each tube was behind a different filter. Those filters are referred to as X,Y and Z plus Xa, Xa was added later.

Analog computers need constant calibration, lamps fail, voltages fluctuate, tubes age, filters solarize, even the temperature causes the readings to change. This was one of my first jobs keeping these old kunkers going just long enough for the company to allocate enough money to buy a newer one. The newer one was also called the D25 but to differentiate it from the tube behemoth the suffix “-2 solid state” was added.

Hunterlab D25-2Δ
(I searched hard but could not find a photo of this machine, If I find one I’ll replace this)

Both models were essentially the same machine, they had to be as by then industries all around the world had written specifications that required that the new one read the same as the old one just smaller, lighter and without the vacuum tubes.

Q: BUT HOW DO YOU READ COLOR? Well I’m glad you asked. The machine does not read the whole color but looks at specific areas and that has been determined to give enough data to make certain assumptions about the color. The real purpose of the machine is to tell how far off the ideal color you are and not the absolute color, that’s a much easier job.

tristimulus color space

Above you can see the four filters of the tristimulus colorimeter. Calibrated plates plus a zeroing mechanism or standards are used to make the readings equil the standards. Once done you can read the percent reflectance of light from your sample. Percent reflectance X,Y,Z does let you write down the numbers but tells little about what color you are looking at.

Mr. Hunter’s brilliant idea

If you are familiar with tools like Photoshop you may have noticed next to the crayon color picker there’s a scale called L,a,b. This is one of Mr. Hunter’s greatest contributions to the world of color. He figured out a way to take the XYZ numbers and output Lab. Lab is great because for the first time you can look at the number and have an idea of what the color is. L is the value of light from very dark to very light, a is the shift from green to red going from negative to positive and b is the shift from blue to yellow. This is called the opponent color scale and works similarly to your eyes as you can see a reddish green or a yellowish blue.


XYZ to Lab

Here’s where the analog computer of the two machines comes in, you take the voltages coming out of the photomultiplier/germanium photocell represented by the formula above and apply that math and your results will be in the appropriate voltages. In the early machine you had to turn a twenty-five turn dial until a meter went null and take your reading off the dial for each reading. On the more modern D25-2 you pushed a row of radio buttons and read the value off a volt meter one reading at a time.

Digital Color Measurement

If you’re interested you can reproduce this experiment if you have a color image editor like Photoshop. Open a photo you took, find the color picker and set the scales to XYZ and Lab. Hover the picker over the color in the image you want to see the tristimulus value for and look in the info panel to see your results. That’s it! If you want to calibrate your image make sure there is one know color standard is in your photograph and use the Image -> Color balance to adjust your standard then read your sample. Wasn’t that easy?

The computer had a special board with a very expensive operation amplifiers that would output a voltage that was the square root of the input voltage, others were multipliers and dividers. These machines lasted a very long time in the field and as they aged many of them could no longer be fully calibrated but this mattered little as their intended purpose was as a color difference meter so we could calibrate them to the customer’s standard and they only had to measure the small difference their production was varying from their standard.

My calibration helper

When I started to calibrate analog computers in 1983 I used this calculator to make sure my conversion results were correct for the range of colors I was working with. I still have this calculator and I had it a few years earlier when I took electronics at college. As you can see you can program in formulas, slide the switch and hit the COMP button and it would query you for XYZ and produce Lab so I didn’t have to carry around any tables. Of course I was holding in my hand what would eventually end the work I was doing.

HunterLab Standards


Above is a photo of my personal set of standards, given to me by my good friend and mentor Randy Bohman when I left after ten years of selling, servicing and installing HunterLab equipment and software. This was an amazing experience to not only travel all over Canada and parts of the world but to meet and work with so many leaders in the field from innovators like Mr. Hunter and Mr. Harold to all the color scientists working in the industry and sitting in on the development of technical standards to be invited into the labs, studios and testing areas of every industry imaginable.

By the late 1980s these machines were heading to the junk pile when the D25-9 was introduced. It could display all the readings at one time on its fluorescent display and used an analog to digital converter that eliminated the need to carry around tables to figure out what was going on. The source/sensor was changed little for the new model.

D25-9 M sensor

The D9 as we called it was a terrific machine and had options out the wazoo like the printer you can see in the photo above. It also had a row of hidden buttons that could contain options like extra memories or color scales. The tomato industry had a special button and so did a number of P&G products, there was also a hidden button that accessed the diagnostics.

This new wonder machine ran on a somewhat propetitery card bus. This was sort of an industrial standard for plug in cards, on one card was an 8088 processor and another card had the ROM and another the RAM, there was a card to run the printer and one to run the display plus a serial card for external communication. The A/D converter was on its own harness and connected directly to the CPU via a wide ribbon cable. Other than the photocell system this was an all digital machine, the end of analog computers at Hunter Associates Lab and the eventual move to spectral data.

Make sure you read my post of meeting and working for Mr. Hunter. Two Color Pioneers and a Kid from Toronto


Raw Power Turns 45 Today So I’ll Write

Some little news tid bit popped up today telling me that as of this day forty-five years ago CBS released Iggy Pop’s “Raw Power”. I don’t remember the day but I do remember that only a few months later I was to be exposed to this album. Thinking about this time brings back a flood of memories that I will try to capture here.

Another LA resident at the time

My family was living in the Los Angeles area and was friends with another family whose father worked for CBS Records, I don’t know what he did but his kids always had an amazing collection of records and it is at their house in the hills that I found Iggy in a pile of records the kids had. The family had two sons, one older was into the heavy metal so he would pick the albums first and pull the Black Sabbath and such out for himself. The younger brother was my age, we didn’t like to listen to the music his older brother so we picked whatever was opposite and that was just by looking at the album art because, who knew?

On the cover “Raw Power” featured a semi naked Iggy with makeup and a snarl, good start. The other album was the equally crazy looking  “New York Dolls” which was first released only two months later. We took the albums to the huge console record player and listened to both. They did not sound like the brother’s Black Sabbath and I knew both he and my parents hated them so we were good on the main points.

So both albums were only a few months old when I discovered them in a huge pile of promo discs and I immediately liked both of them as I do today. Good start if I do say so myself but sadly this was not my start as I already had a record collection and was allowed to use the family record player where my kid sister had to make due with her “close and play”.

The first record I bought with my own money and I think I bought it a J.C.Pennys was a 1960s live recording of the Beach Boys. I also had a copy of “There Goes Rhymin’ Simon” by Paul Simon and quite coincidentally also released in 1973. This album is a classic and likely has sold many times the total of both previous one but not as raucous and revolutionary as either. I think this one was a gift from my grandmother who was living in California at the time.

I also got to go to a few concerts in those years in California, my friend and neighbor had his birthday party at a local amusement park with included a concert at the park. We got to see Kenny Rogers and the First Edition, yep that Kenny Rogers except all dressed in a pastel jumpsuit. Seeing “Just Dropped In” live must have done something to me, I know it did to the band as this was their last performance.

I also remember getting taken to other shows, we went to the Hollywood Bowl for a Classical performance but can’t place the piece or players. Then there were the Christmas performances of the opera and ballet at the Shrine Auditorium but it wasn’t until we returned to Canada that I started to go to concerts of my own choosing.

Five years later in 1978 my dad moved us to the country where I rode the school bus with pig farmers kids and went to a high school with more pregnant kids than I’d ever seen in my life. I had two friends and a girlfriend the whole year. One of the friends was a kid who reconized me from the school I went to the previous year, he knew it was a bad scene and he spent every moment trying to get back to Toronto so I didn’t see much of him. The girlfriend was crazy, and the other friend was totally into rock and roll.

I got myself a job at the local record store that had just opened, my job was to assemble the displays and hook up the stereos. The owner knew nothing about such things and paid me off in records and promo items. I also was in charge of the weekly hit lists, a large poster would arrive in the mail which I’d tape to the front window and a stack of smaller printer ones I’d put half on the counter and half take to school which the other kids liked and brought business to the shop.

It was this year that I got to go the first concert of my own choosing and boy what a choice. The school had an open arrangement where if enough students wanted to go to a concert they would set up a ride, on the list I saw that they were willing to take a group to see the Tubes. I signed up with only three other students and a teacher drove us down and dropped us off in front of the Maple Leaf Gardens with the instructions that we were to meet him parked on the street a block north of the building.

The Tubes were amazing, the band was in their super theatrical stage with many costume changes for this highly sexualized show. Warnings were issued about the show too but luckily none had filtered down to my rural school, the singer was said to appear naked and to have simulated sexual acts on the stage. The dancing girls would appear for one number in cheerleading costumes and the next in leather bras and panties, Fee splashed himself from a bucket and rub it all over one of the girls it was crazy and I loved it. I was bitten and had to see more live shows.

The next year we moved back to the city where I had access to the subway and a myriad of clubs and concert halls. Being a fan of CFNY from living in Brampton two years ago I knew what kind of music I liked but being on the fringe of the antenna could no longer hear them and had to make due with some late night shows on CHUM-FM until they got a stronger antenna.

It was listening to these late night shows that I won tickets to the two most important shows to hit Toronto. This is going to sound crazy but I called in both times and answered questions live on air for the tickets and I remember how it went in both cases. Announcer says they have tickets, in this case the Clash at O’keefe Center. First person who guesses the current album gets them. I shout out “Give ’em enough rope” and run for the phone, about twenty minutes later and dozens or wrong answers I win them. Totally crazy show, imagine the Clash at a fancy opera house? I’d call it a DIY mosh pit where the fans try to make a pit from rows of seats. There’s video online of the aftermath, my radio station seats were close and I could see it but it didn’t look like the damage afterward. All I have to say is the band was encouraging it to happen by being so damn good.

The other show was The Ramones at the New Yorker on Yonge St. Now the Ramones had been to Toronto a number of times by now and the New Yorker a few times plus they had released a few albums so you’d think the biggest rock and roll station would have some knowledge of what and who they were but no. Announcer, “First three callers with the right answer gets pairs of tickets to the Ramones, What do the Ramones and Paul McCartney have in common?” Same thing, a bunch of callers get it wrong for like half an hour. I get the second pair and the announcer gets tired and gives the third to a joke answer about the amount of grease in their hair. McCartney also used the last name Ramone.

I must have won a pair of tickets but I went alone, I don’t remember anyone at the time liking this music, I don’t even remember selling the extra ticket. I just remember the Ramones and hanging this poster on my locker door in high school.

There was one other kid in my high school who liked to talk about strange and unknown bands, he was two years older and we only met during his last year there but he had a great influence. I’m sorry I don’t remember his name but he was not a punker, he was more into progressive and art rock and spoke about other bands like Gong, Soft Machine and David Allen.

This high school was a tech school and had a lot of different shop and music and art classes which made it fun to go there but it drew kids from a wide area so there was not the closeness of a school where everyone lived in the neighbourhood. This student was also a real oddball, he was known as the smartest kid in the school and he openly spoke about LSD making you smarter so he was a real pain in the ass to the school who wanted the grades but not, well everything else about him including the way he dressed only in black and wore a long coat everywhere.

We talked about music, I didn’t do LSD and I finagled meeting up with him for a few shows he was going to and these mark my first trips to The Edge in Toronto. I don’t remember which was the first show but we went to see Pere Ubu and on another night Mink DeVille. We didn’t drink, well he just didn’t drink and I was two years underage and without him ordering beers I wasn’t going to risk getting kicked out which I only later found out was pretty hard to do there. The one time I was with a group of guys who got kicked out we had to get caught pulling down and ceiling and breaking up the pieces and even then they were strangely reticent and only officially kicked out one guy and we mostly left to give him his jacket since it was snowing.

The next year I met my now very dear friend Jeff, at the time we’re still underage but bold enough to try to get in to the clubs. Places like The Edge were open all day and served food so we’d go early buy food, make sure there were beers on the table at shift change and we not only get served but we’d dodge the cover charge which went to buying more beer. Wayne County was one of my favorites. There weren’t a lot of people going to these shows so very quickly you’d recognize people and they’d recognize you so if there was a question of your age you could quickly shout out and people who didn’t know you would vouch for you, like community.

I’ve seen all the acts in the above poster. This particular Viletones show is the one were Jeff almost got beaten up by Leckie because Jeff was trying to talk to him while the guy was pissing. Leckie grabbed him and said “Why are you trying to look at my dick?” then the band rushed in and said he couldn’t beat up Jeff because they had to go on stage and off they ran with Lecking shouting that he wanted to meet him there after the show. We didn’t.

Here’s another show we were at, opened by the Demics who we liked as they were formed from another band we would go to see at Larry’s and that was Crash Kills Five. The thing about these early shows was that not only were the clubs run down and stank but you weren’t always sure you’d get a show at all. The Viletones would often cause fights and just not play but not this night, they were killer. “Oh there’s no hope for me!”

If I think of anything good I’ll write more, maybe something about this and the cops…

Me with Joey 1979

I’m very proud of my anti-backlash five start acme nut

I know it’s beautiful isn’t it? I’ve been using and researching acme screws for about ten years and at one point had access to a fancy acme tap which has since gone missing and that’s a shame as it cost a few hundred dollars. This tap would have allowed me to create the same style anti-backlash nut as shown above but in a more solid material like brass or steel.

Thanks to some kind thingiverse user I found a cad model for this exact thread and I used it to 3D print a few hex nuts just to see if it worked. When I printed and then threaded the nut it was a bit more than surprising that I could actually print a thread, mind you a 1/2″ acme thread is about as course as you’ll ever see this side of ship or bridge parts. 

In the cad image above you can see clearly how the threads on a five start acme nut work. The springs apply tension to keep the nut from wobbling on the threads so the small nut is located from turning by the 10-24 bolts. Better hardware would be some kind of shoulder bolts and I will keep my eyes open for them but for now the tiny threads pose no problem for the amount of travel required here.

The test fixture pictured above allows some torque to be applied and the deviation measured by a dial gauge (not pictured, sorry) Meccano is handy for quick fixtures.

Here’s the nut mounted to the side of my Y axis gantry.


Another shot of the gantry.

If you’d like to see the CAD files check out my Thingiverse page.

When cancer comes home

I haven’t mentioned this here because I don’t like to talk about it but now that the worst of it is over I’m feeling a bit more able to not only put my words down but to be able to read them. My wife was diagnosed with cancer one year ago today. I’ve been with her every step of the way supporting her and holding her hand and doing things I never thought I’d be able to do. Scary things too but not only did I manage to do them I somehow excelled at it as all the compliments from doctors, nurses and generalists attested to.

Okay I kind of made up that last part but at the start of this I did almost pass out a couple of times when they were drawing blood. I didn’t know it was going to happen as the room slowly turned grey and the nurse said I should go for a walk and get some air, I didn’t even know she was watching me!

I quickly got used to seeing them poke needles into her but it brought up some thoughts about myself and how I have never taken care of anyone before. I hadn’t even done a very good job of taking care of myself up until now. As a full grown adult I was not proud of this but now I’ve come to terms with it and have moved on.

Theresa is feeling much better now and has returned to what we believe is normal or is going to be the new normal. You know she’s a writer and has kept a pretty through blog about the events of the last year but a warning to those who are easily disturbed as she pulls no punches, you get the real deal here. Well you have been warned. Happy-Cancerversary!

The Big Fish Eat Everything

garbage truck

I just got a lesson in free market economics. My local garbage collection company was bought up by a huge multinational corporation. We’re told that economies of scale and market forces determine costs, while this may be true if you are operating the company it has little to do with what the consumer pays for services.

The first change we noticed that our pickup time started to move all over the place and we have two collections, one for recycle and one for waste and they could pick up one early in the morning and the other in the late afternoon. There was suddenly no consistency which forced a change in my schedule as I used to put the cans out when I took Theresa to work in the morning but now I had to put them out Sunday night to make sure wouldn’t miss the pickup.

Next change was the sudden arrival of a new recycle wheelie bin, it’s nice to have a clean new bin but this one also happens to be slightly smaller and since in our area we are limited to using this bin only it is a reduction in service or in other words an increase in our cost.

Finally I notice a couple weeks back that they have neglected to empty my new smaller recycle bin. A week later the bin is emptied but not the next week. I dig out a flyer they sent us and it stated that from now on we were only getting recyclables picked up every other week.

These changes mean that we’re getting more than a 25% reduction in service while paying the same fees. If this were an isolated event I might say it was just the unintended side effect of merging two systems but this happened when our local internet provider was bought out by a huge national carrier and when our local cable provider was bought out by a huge corporation.

Huge corporations are only more efficient when it comes to making money for themselves but when you’re a customer they take every advantage to leverage their huge size against you the tiny individual customer in what can be easily compared to a mafia style shakedown. There are few other advantages to companies growing this large, they don’t support my local area as the head office is way down in Texas and all the good paying jobs are there too all we have is the labor and they take the profits and things like the local professionals that used to service the old company are moved elsewhere.


When is a company not a company?

I’ve recently become aware of a couple examples of how much the world has changed while it tries to conceal this fact. In my first example is something I had know about but since not being an insider did not understand the implications. I believe we have huge portions of the economy that are basically false advertising and are getting away with it because it happened slowly over a long period of time.

I have a friend that I’ve known for likely ten years, we met at a blogging site but since have met in person a number of times. He worked as a highly skilled assembler of  aerospace parts, something he thought was safe until his company moved overseas. This move happened at a time that a number of other companies pulled the same move and suddenly there was a glut of highly skilled workers and he was forced to come to grips with his future being shattered and at the same time expected to recareer.

He took some time off and decided he’d like to drive a truck. Long range and complex loads were for him as he could pass the tests and acquire the licenses being a pretty sharp guy with a mechanical background. He did this quickly and was on the road but it soon became evident that the same big business ethics that dumped him on his ass in another industry were at play in his new role.

The company he works for is called a trucking company, they advertise the service of trucking but they don’t own any trucks. The modern way to operate is to put up a sign and hire a room full of office people that pose as a trucking company but when an order comes in they “hire” a trucker like my friend to move the goods. This way the company does not have to pay truckers as employees even though they are posing as a trucking company. They also don’t have to maintain any equipment since all that is the employee’s I mean “contractor’s” responsibility. You see what is going on here?

I was a little shocked to learn this as it came out slowly because this is an accepted practice, for now. When he posted about buying a truck I did not understand that he was reaching into his own credit to buy that truck that immediately was sent to the paint shop to have the company colors applied, his name and his first name only appeared in tiny letters near the door.

Later he wrote about how the company used numerous tactics to get out of paying him, like how he would be called for a pickup at a certain time and then made to wait hours that he would not be paid for. They also penalised him for not making connections that were impossible if not illegal to make. Since the company had divided the work over numerous small contractors they were able to take advantage of them being the big fish while the driver was the easily replaceable small fish.

Even though he owned the truck and made all the payments he was not allowed to take any jobs from anyone else which is odd as you’d think that being under the complete direction of one employer would instantly make you an employee.

You should not be allowed to present your company as something it is not. If you call yourself a trucking company you should not outsource your entire business, what they are is brokers and not truckers and deserve no exclusive rights without offering employment.

Here’s my second example in this early similar scenario that reared its ugly head about 18 months ago when I spoke to a local fellow who does groundskeeping. The fellow said he also worked as a roofer actually he said his main skill and trade was as a roofer but had to supplement his trade and chose to call himself a grounds keeper because there are laws that prevent him from calling himself a roofer.

We spoke more and he had an interesting story. It seems that the local industry of those who legally call themselves roofers are actually just roofing brokers with signs and business cards that falsely purported them to be actual roofers as they have no hammers and no trucks and worst of all no employees but they do have a lic. and those are limited and hard to get.

The trouble is his “boss” only calls him when he has a job, actually bosses as he contracts to a number of “license holders” who not only expect him to show up at a job site with one day notice but if you can’t because you are finishing another job they often penalize them for it by withholding future jobs. Worst of all with this new system of exploit the lowest is as a contractor he is no longer able to claim unemployment during the winter months as he used to when he started in this business as an employee.

He’s on his own for the bad times and it seems for the good times as well as the company scoops the bulk of the profits because they can. All these changes were know about in advance by those who perpetrated them, it was only a surprise for those who were negatively impacted.


Lightning strikes, lights flash, Mac stops.

This is what now passes for my server room. Gone is the 200 square feet of serviceable lead acid batteries or raised floor and halon fire system but in return I have, well I have smaller problems.  Okay what I have now is two cable modems, one for internet (bottom) and one for phone service (top), a 24 port 10/100 switch and an Apple Time Capsule. The Time Capsule has three gigabit ports two of which go to my two Macs and the third goes to the switch to service everybody else in the firm and by firm I mean just a couple of boxes for mostly entertainment so there. I also distribute wi-fi to service the wireless devices on the network, you know stuff like a couple of phones and a tablet. There’s one more thing, it’s a UPS further down where you can’t see it and that pretty much makes up for the server room and not even a single glass wall in sight.

Now back to the story, last night after the light show and the noise and the flickering lights I went to the studio to shut down when I found the Mac on an endless loop of rebooting and restarting. Something had damaged the system format and it was unable to complete the boot cycle. After a few rounds of fsck and some disk diagnostics plus the old four finger startup and four “BUNG”s I determined that the drive needed to be reformatted and the system reinstalled.

Image result for apple failed hard drive

Normally this is a tragedy but I’ve been planning ahead, when we moved here I had to buy a cable modem for the new system, at the old house I just split the cost of internet with my neighbor and pointed my wifi antenna at his basement window & job done, worked great for years. Now I had to buy equipment. TWC wanted to sell me their “high end” wireless router but some research said it was an overpriced piece of junk and I’d be better off getting my own. Some writers even claimed that if you used the TWC unit they had access to your network and could read your rants and turn on your webcams. Time to put on my tin foil hat and crack the books.

Not wanting to wear the hat of shame I located a great deal on an Apple Time Capsule. It’s a router, a wi-fi connection point, a print server and had its own hard drive for backing up other computers. All you have to do is run Apple Time Machine as shown below and both my Macs will be safe. There were safe for almost three years up until last night. I do daily backups but don’t turn the machines on every day which gives me a pretty good snapshot to work with.

This is how Time Machine looks if you need it while the system is running which mine wasn’t. You can find lost files and draw things out of your archive if you need to.

My system is not functioning, I have a backup but I’ve never had to restore from that backup. I bite a bullet and reboot. Now comes the tricky part, I hold down the command key until this pops up. Tricky part over.

Clicking “Recovery HD” finds my backup on the network and all I have left is to click start that’s it, takes a couple of hours but no other input is required on my behalf. This article says what I just did dosen’t work, I beg to differ but I don’t have a fancy column in a fancy Mac trade paper turned web site. He actually describes a scenario that was totally unlike what I had just gone through. I check the date of pub and it’s barely a year old, could it have changed that much in a year? He sounds like some kind of crazy doom sayer.

Image result for the end is near

I wish I had more to say but I don’t, it just worked and I’m back to work. The machine that everyone says is too expensive just cost me nothing to fix, I didn’t have to call in the Geek Squad and my hardware is still good enough to do the job it was doing yesterday. I will replace the batteries in the UPS that supplies the sensitive gear in the studio but that’s it. -See you later.