colour analyzer, can I use it?

Mick Fagan · Apr 25, 2017

darkroommike said:
LOL In my opinion it's just cruel to recommend pieces of equipment that haven't been made in 20-30 years. A person could go "batty" trying to track down good examples of all three. The Colorbrator is a neat piece of kit but has not been made since the 90's, the Color key is just a bit of Formica, you can substitute Wilsonart North Sea D90-60, very neutral (126 128 128 in Photoshop) and reflects about twice as much light as a gray card, and I haven't seen a new Wallace Expodisc in years, either. The other issue with old color printing "tools"? How do you know if said tool is still neutral and not faded? I pulled out a Kodak "Shirley" reference this weekend and even with dark storage it had faded considerably and not evenly in all three colors.

I agree it isn't called a Wallace Expo Disc these days, but (I believe) his daughter runs the business and brought it up to date for use with electronic photography, with which you seem to understand reasonably well; if your photo shop reference in your post is accurate that is. The current Expo Disc works the same as the original Wallace Expo Disc. I have a friend who bought the Expo Disc (referred to below) last year for use on his electronic camera. He purchased the Expo Disc after first using one of my Wallace Expo Discs, hardly believing the almost instant correct colour calibration he obtained.

Dead Link Removed

Mick.

Berri · May 1, 2017

today I did a quik test on getting the best calibration values for my colorstar paired with my darkroom conditions. I printed a test frame shot on Kodak ektar 100 in perfect light conditions, blue sky with some white clouds around 3:00pm, it is a portrait with a grey card. I balanced to get neutral grey and it came perfect with that values i calibrated the instrument. Now i switched to a portra film and cut the last bit of film with no picture, just the film base and made a sandwich with a kodak projecting scale as you see in the picture below, placed in the film holder and nulled the instrument while the probe was under the grey rojection scale plus the film base. I contact ptinted the whole film and the balance was spot on.
I think there's no need to waste frames to shoot a grey card when you colud do this!

as you see in this photo the grey card I'm holding in the frame (yes that is a portrait of myself) is the same shade of the grey in the kodak projection scale.

rpavich · May 1, 2017

Ok....trying to wrap my mind around this.

Instead of shooting a grey reference in each roll and lighting condition (ala Mick) you use the exposure wheel thing and null off of that+film base.

Does it matter which density on the wheel you choose?

Also, one thing that I've noticed is that using Mick's method your color is spot on the first time every time ..but getting the correct density in the print still requires a test strip. I haven't found a fool proof way to get that in one shot.

This is interesting, I might give it a whirl.

PS: I'd be very interested in seeing what a finished print looks like with this method.

Berri · May 1, 2017

I used the triangle with the number 4 because it seemed to give the same density as the actual grey card I shot. But other sections of the projection scale didn't differ much. After selecting the filter pack with this method I proceed as usual, using the analyzed to determine the exposure time in the area of the frame with medium density. It works great! If you think about it, grey remain s grey even in negative, that is why it works. I tested it on ektar, portra and gold. Tomorrow I'll make more tests

markbarendt · May 1, 2017

What Berri has suggested generally works for a given lighting situation. Change the light source and it doesn't.

Essentially it balances to daylight as Berri designed it.

Berri · May 1, 2017

I'll see if I can make a video, it's easier to see than to say

Berri · May 1, 2017

markbarendt said:
What Berri has suggested generally works for a given lighting situation. Change the light source and it doesn't.

Essentially it balances to daylight as Berri designed it.

Yes and no. The film is ment to be used in a certain light situation, 5500K in my case, and if you change light situation the colours shift naturally, but that's not a printing fault. Of course you could adjust a little when printing, but technically speaking you should use CC filters during the shot to convert the light

Berri · May 1, 2017

This method should give you an accurate rendition of the actual complementary colours on the film, then of course you could adjust to taste

rpavich · May 1, 2017

Berri said:
I'll see if I can make a video, it's easier to see than to say

That would be useful, please do.

markbarendt · May 1, 2017

markbarendt said:
What Berri has suggested generally works for a given lighting situation. Change the light source and it doesn't.

Essentially it balances to daylight as Berri designed it.

Berri said:
Yes and no. The film is ment to be used in a certain light situation, 5500K in my case, and if you change light situation the colours shift naturally, but that's not a printing fault. Of course you could adjust a little when printing, but technically speaking you should use CC filters during the shot to convert the light

Actually I'm wrong, and I think you are too.

I don't think I can explain it concisely. I'm thinking you are finding a special case rather than a dependable rule.

Berri · May 2, 2017

markbarendt said:
Actually I'm wrong, and I think you are too.

I don't think I can explain it concisely. I'm thinking you are finding a special case rather than a dependable rule.

could be. As I said I trid this with three different films and it did work. But I can't say it will work for every film. I think as long as the dyes on the film are close enough to the complementary colours of actual world it should work. In the case dyes differ it won't work.
I would spare some of my time to read your opinion on this, why do you say we both are wrong? explain please!

Berri · May 2, 2017

markbarendt said:
I'm thinking you are finding a special case rather than a dependable rule.

How do you answer this, what is the actual colour of a grey card photographed on film if you could exclude the orange mask? If the answer is grey then I don't see how this method shouldn't work.

Berri · May 2, 2017

Just did another test of this method with two old negatives of mine. The first one was a fuji pro160ns and the second an old type portra 160nc. it didn't work. the first came out very yellow, the second one cyan. both frames were portrait in almost perfect ldayight situation. I tried to actually expose and process the kodak projection scale through the portra 160nc film base and it printed grey. Is it correct to say that the actual dyes on those two films are not the exac complementary of the real colors?

rpavich · May 2, 2017

Why am I not getting any notifications about this thread? I'm subscribed.

Berri · May 2, 2017

I think I'm figuring out why it can't always work. The cyan forming layer has magenta coloured couplers and the magenta forming layer has yellow coloured coupler. This two coloured couplers reduce some of the unwanted absorption in the layers acting as filters; In the cyan forming layer the magenta coloured coupler will reduce absorption in the green portion of the light, and the yellow coloured coupler in the magenta forming layer will reduce absorption in the blue part of the light. The yellow forming layer has a better curve and there is no need to introduce coloured coupler to reduce unwanted absorpion. During the developing process the couplers are used to form the final dyes, and the residual coloured couplers will form the orange mask (yellow coloured coupler+magenta coloured coupler) therefore the orange mask is inversely proportional to the ammount of formed dyes. This means that if I take a perfectly exposed and processed picture of a neutral grey card in perfect light condition for the film in use, it will produce a negative with the same density in all trhee layer (or anyway a density so that in transparency it will produce a grey) plus some residual yellow and magenta coloured couplers. My method used a neutral transparent gray overlaid on top of a non exposed but processed film (the tail of the film), in this area the ammount of mask is at its maximum, so the balance of the gray may not be the same of the grey card photograph, where the mask is at its medium.

Don't know if I made myself clear, please understand english isn't my mother tongue

markbarendt · May 2, 2017

Berri said:
How do you answer this, what is the actual colour of a grey card photographed on film if you could exclude the orange mask? If the answer is grey then I don't see how this method shouldn't work.

That's actually my point Berri, when the grey card is photographed in the scene it is not a perfect neutral grey; what the camera sees is the color of the light falling on the grey card plus the color of the grey card itself. This changes every time you change light sources for example when the light is leaning blue (subject lit by open sky) the card looks more blue to the camera. When the light is incandescent and much more yellow, the card looks yellow to the camera.

In both of those cases (in fact any property processed case) the mask remains the same.

A face (for example) is affected by changes to light color in the same way as the gray card in the same scene, under the same light, facing the same way is. Your grey target in the enlarger is not affected by the light in the scene.

markbarendt · May 2, 2017

The other thing the grey card in the scene provides is a real luminance reference, independent of color. That is a very important reference for getting color work to look right.

Berri · May 2, 2017

markbarendt said:
That's actually my point Berri, when the grey card is photographed in the scene it is not a perfect neutral grey; what the camera sees is the color of the light falling on the grey card plus the color of the grey card itself. This changes every time you change light sources for example when the light is leaning blue (subject lit by open sky) the card looks more blue to the camera. When the light is incandescent and much more yellow, the card looks yellow to the camera.

In both of those cases (in fact any property processed case) the mask remains the same.

A face (for example) is affected by changes to light color in the same way as the gray card in the same scene, under the same light, facing the same way is. Your grey target in the enlarger is not.

Let me rephrase; If you could exclude the orange mask, what would be the colour of a grey card photogrphed under 5500K with a daylight negative film?

Berri · May 2, 2017

as you can see, in a maskless film the grey remains grey. I assume this picture was shot under standard daylight conditions.

Berri · May 2, 2017

in the picture above, you may say that the grey is not neutral and there is a slight cast. But in my last experiment I didn't encountered just a slight cast, but a major colour shift. For example the picture shot on portra 160NC and printed with my method that came out extremely yellow was like it was shot under sodium vapour street light with daylight film.

Berri · May 2, 2017

Next time I order films I'll buy some of this rollei CN200 to see if I can figure things out better

markbarendt · May 2, 2017

Gerri the principle at play here actually stands independently of the film.

The relationship between the gray card in the scene and the subject matter in the scene is what's important.

The grey card gives you a reference point to objectively measure variances in scene lighting and null out the differences so that, for example, skin tones always look the same.

IMO that doesn't mean the skin tones will always look appropriate, it means the skin tone you print under daylight conditions can be printed the same as skin tones under incandescent lights. In either case you simply adjust the enlarger filters to print the grey card as normal.

MattKing · May 2, 2017

Your tests through the unexposed film deal with the nature of the film itself.
They don't deal with the light used to expose the scene.

Gerald C Koch · May 2, 2017

At one time Kodak supplied a standard negative and print in their Color Darkroom Guide. Very helpful in getting things going. It also contained a series of viewing filters to estimate what change be used to correct the color balance.

https://www.amazon.com/s/?ie=UTF8&k...qmt=b&hvbmt=bb&hvdev=c&ref=pd_sl_2jf73a670q_b

Berri · May 2, 2017

markbarendt said:
IMO that doesn't mean the skin tones will always look appropriate, it means the skin tone you print under daylight conditions can be printed the same as skin tones under incandescent lights. In either case you simply adjust the enlarger filters to print the grey card as normal.

No sorry it doesn't work that way. if you take a photo of a portrait with a grey card under tungsten incandescent light (2800-3200K) with a daylight film and you try to balance the tones with the enlarger you'll encounter many trubles and eventually you won't get a natural looking image anyway, because if you make the grey card look grey all the other colours go all over the places. What you want to do is to correct before you take the photo either with CT filters on the light or CC filters over the lens. Anyway we are talking about two different things here. My intent wasn't to produce the best image, but to produce the actual complementary image present on the film, whether it is good or bad in terms of colour. I don't know if I'm making my self clear.

Gerald C Koch said:
At one time Kodak supplied a standard negative and print in their Color Darkroom Guide. Very helpful in getting things going. It also contained a series of viewing filters to estimate what change be used to correct the color balance.

I have the viewing filters, and my own standard negatives, if I want to produce a correctly balance photo I have my means to do so, what I'm trying to do here is to investigate if I could find a quick and easy way to produce a print with the exact colours as it is on the film, but complementary of course.

Now, my first experiment can't work for a very simple reason which I already explained a few post earlier. Also it occurred to me that placing a neutral transparent grey on top ov a negative base doesn't make much sense because by doing so I would simply add some neutral density and I may as well remove it and analyse the film base alone. Infact I did it with the films I proved to be working with this method and there was no difference.

colour analyzer, can I use it?

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