Tmax 400 Film for Color Separations

[ciocc]

Hello. I came across a photocopy of an old article that appears to have been written some time ago, apparently around the time Tmax film was introduced. It stated that until the "recent" introduction of two Tmax films, it was next to impossible to make direct in-camera color separations with roll film, because of the different development times required for the RGB negatives. With the introduction of the two Tmax films, it was now possible to do so, because the two Tmax films have a special property of developing to the same contrast index for a given development time when exposing the film through the RGB separation filters. The article goes on to explain a process for making in-camera separations on roll film with Tmax and two films are mentioned: Tmax 100 and 3200. There's no mention of Tmax 400.

Does anyone know if Tmax 400 also shares that property? When I look at the Tmax tech pub, there's no specific mention of that property, but there's some language that suggests the property, but that language is only associated with Tmax 100.

I'm probably going to have to test it myself, but thought I'd ask. I had no idea that Tmax 100/3200 had that property. If Tmax 400 also shares that property, it will make my project considerably easier.

Thanks.

 

[Donald Qualls]

So, in essence you're asking if the contrast curves are the same for exposure in red, green, and blue light for T-Max 400 (TMY-2) film?

 

[Lachlan Young]

Hello. I came across a photocopy of an old article that appears to have been written some time ago, apparently around the time Tmax film was introduced. It stated that until the "recent" introduction of two Tmax films, it was next to impossible to make direct in-camera color separations with roll film, because of the different development times required for the RGB negatives. With the introduction of the two Tmax films, it was now possible to do so, because the two Tmax films have a special property of developing to the same contrast index for a given development time when exposing the film through the RGB separation filters. The article goes on to explain a process for making in-camera separations on roll film with Tmax and two films are mentioned: Tmax 100 and 3200. There's no mention of Tmax 400.

Does anyone know if Tmax 400 also shares that property? When I look at the Tmax tech pub, there's no specific mention of that property, but there's some language that suggests the property, but that language is only associated with Tmax 100.

I'm probably going to have to test it myself, but thought I'd ask. I had no idea that Tmax 100/3200 had that property. If Tmax 400 also shares that property, it will make my project considerably easier.

Thanks.

From what I understand, the first TMax 400 has an issue with one of the separations rolling off in the shoulder before the others if you develop them all to the same CI (like you would on a single roll of film) - or possibly something like that - it's covered by one of Bob Pace's 'Keeping Pace' newsletters - I'd need to go and do some extensive hunting to find what he described the problem as. Since then, TMax 400 has been significantly revised (including the colour sensitivity), so you'd need to do some testing (including densitometry etc). This isn't to say that you can't use any film to make separations, it's just that you may need to adjust things to fit your process.

 

[removed account4]

you might be able to find some information here: https://galerie-photo.com/test-trichromie.html

have fun with your experiments !
John

 

[Bill Burk]

Seems like something I could verify with my new HD sector wheel...

 

[ciocc]

So, in essence you're asking if the contrast curves are the same for exposure in red, green, and blue light for T-Max 400 (TMY-2) film?

Yes. The documentation states that the curves are the same for Tmax 100 and 3200. Silence regarding T-max 400. It will make my job of making separations much easier if I can develop all three negatives for the same time and get the same contrast. Why not use Tmax 100? Because I'll be printing the negatives using an alt-process that requires contact printing under UV light. Tmax 100 has UV blocking layer incorporated in it that makes that film pretty much useless for alt-process. Tmax 400 does not have that UV blocking layer.

 

[ciocc]

From what I understand, the first TMax 400 has an issue with one of the separations rolling off in the shoulder before the others if you develop them all to the same CI (like you would on a single roll of film) - or possibly something like that - it's covered by one of Bob Pace's 'Keeping Pace' newsletters - I'd need to go and do some extensive hunting to find what he described the problem as. Since then, TMax 400 has been significantly revised (including the colour sensitivity), so you'd need to do some testing (including densitometry etc). This isn't to say that you can't use any film to make separations, it's just that you may need to adjust things to fit your process.

Yes, at the end of the day, I'll need to do my own testing. I'll have to buy a box of Tmax 400 and verify.

 

[nickandre]

Ansel Adams had a note in his book that panchromatic films often require a filter to achieve true panchromatic response.

My understanding is that you should be able to correct this with relative exposure (i.e. using a color + specific ND filter) for particular layers. The process of exposure should affect the same fundamental unit (the same halide) unless there are some weird non-linearities when the halide is activated through the sensitization dyes. Barring that, the calibration is presumably not too bad as long as you can establish uniform curves on neutral colored cards through the reasonable exposure values.

 

[relistan]

Not an answer to the question, but if you are looking for results that are nice, @dourbalistar has done some pretty cool Trichromy with Ultrafine eXtreme: https://www.rangefinderforum.com/forums/showthread.php?t=171323&highlight=trichromie

 

[Nicholas Lindan]

Ansel Adams had a note in his book that panchromatic films often require a filter to achieve true panchromatic response.

Early panchromatic film tended to be overly sensitive to blue and so a yellow filter used to be de-riguer to prevent a white sky.

Modern films have fixed this problem. But they do have a small dip around 500nm - cyan. As, outside of Caribbean seas, there is nothing cyan in nature this is of little consequence.

 

[Lachlan Young]

Yes. The documentation states that the curves are the same for Tmax 100 and 3200. Silence regarding T-max 400. It will make my job of making separations much easier if I can develop all three negatives for the same time and get the same contrast. Why not use Tmax 100? Because I'll be printing the negatives using an alt-process that requires contact printing under UV light. Tmax 100 has UV blocking layer incorporated in it that makes that film pretty much useless for alt-process. Tmax 400 does not have that UV blocking layer.

You might also want to test Delta 100 or FP4+ or something like Adox CHS II for making separations - especially as they are available in a wider range of sizes.

Can you be a little clearer regarding the process you are trying to do? Are you looking to make in-camera seps, then contact print them - or are you looking to separate pos/ neg images already made?

I take it you have read up on most of the Kodak dye transfer documentation regarding separation techniques/ potential masking etc?

 

[ciocc]

You might also want to test Delta 100 or FP4+ or something like Adox CHS II for making separations - especially as they are available in a wider range of sizes.

Can you be a little clearer regarding the process you are trying to do? Are you looking to make in-camera seps, then contact print them - or are you looking to separate pos/ neg images already made?

I take it you have read up on most of the Kodak dye transfer documentation regarding separation techniques/ potential masking etc?

I use FP4 for making monochrome carbon transfer prints. FP4 will absolutely work for direct, in-camera seps, as well as many other films. Unfortunately, the red, green and blue filter negatives do not develop to the same contrast when using the same development time for all three. This will result in color crossover. Normally, you have to run tests to determine the development time needed for each sep to produce equal contrast. This is the standard practice. With Tmax 100, you do not need to do this. All three negatives will develop to the same contrast. So I can put all three sheets in the same tank and develop once. Done. Saves time. I'm just hoping that Tmax 400 has this same property. The process is 3 color carbon transfer. I've been doing some research and it appears that with color assembly processes, the required density range is much lower than with monochrome. So I may be able to get away with Tmax 100, since the extra exposure time required because of the UV blocking may be compensated by a much lower density range for the CYM printers than with a monochrome printer. I've read up on dye transfer and well as many older texts (1800's to early 1900's) on color assembly processes. At the end of the day, I'm just going to have to spend the money and buy a box of Tmax 400 and run some tests.

 

[nickandre]

I use FP4 for making monochrome carbon transfer prints. FP4 will absolutely work for direct, in-camera seps, as well as many other films. Unfortunately, the red, green and blue filter negatives do not develop to the same contrast when using the same development time for all three. This will result in color crossover. Normally, you have to run tests to determine the development time needed for each sep to produce equal contrast. This is the standard practice. With Tmax 100, you do not need to do this. All three negatives will develop to the same contrast. So I can put all three sheets in the same tank and develop once. Done. Saves time. I'm just hoping that Tmax 400 has this same property. The process is 3 color carbon transfer. I've been doing some research and it appears that with color assembly processes, the required density range is much lower than with monochrome. So I may be able to get away with Tmax 100, since the extra exposure time required because of the UV blocking may be compensated by a much lower density range for the CYM printers than with a monochrome printer. I've read up on dye transfer and well as many older texts (1800's to early 1900's) on color assembly processes. At the end of the day, I'm just going to have to spend the money and buy a box of Tmax 400 and run some tests.

Shouldn't you be able to fix that by stacking a fractional ND filter on the colors that get more density? Presumably the issue is differing sensitivity for different frequencies which can be compensated with exposure. A densitometer and a few ND filter attempts should validate this -- basically you want to add ND to the color filter for the separation where the curves that come in higher to bring them to the lower one, and then adjust overall exposure times to get the desired density overall.

 

[Lachlan Young]

I use FP4 for making monochrome carbon transfer prints. FP4 will absolutely work for direct, in-camera seps, as well as many other films. Unfortunately, the red, green and blue filter negatives do not develop to the same contrast when using the same development time for all three. This will result in color crossover. Normally, you have to run tests to determine the development time needed for each sep to produce equal contrast. This is the standard practice. With Tmax 100, you do not need to do this. All three negatives will develop to the same contrast. So I can put all three sheets in the same tank and develop once. Done. Saves time. I'm just hoping that Tmax 400 has this same property. The process is 3 color carbon transfer. I've been doing some research and it appears that with color assembly processes, the required density range is much lower than with monochrome. So I may be able to get away with Tmax 100, since the extra exposure time required because of the UV blocking may be compensated by a much lower density range for the CYM printers than with a monochrome printer. I've read up on dye transfer and well as many older texts (1800's to early 1900's) on color assembly processes. At the end of the day, I'm just going to have to spend the money and buy a box of Tmax 400 and run some tests.

OK - I suspected it might be colour carbon you were working with. Short answer is that the pre-2007 TMY was reported to have the same issue you find with FP4+ - and apparently seemed to shoulder the blue separation earlier as well. I wouldn't want to make assumptions about TMY-II without tests, but I do note that it seems to suggest reduced blue sensitivity under an equal energy illuminant - at least as per the data sheet.

 

[nickandre]

Early panchromatic film tended to be overly sensitive to blue and so a yellow filter used to be de-riguer to prevent a white sky.

Modern films have fixed this problem. But they do have a small dip around 500nm - cyan. As, outside of Caribbean seas, there is nothing cyan in nature this is of little consequence.

Very cool! Thanks for the pro tip

 

[ciocc]

Shouldn't you be able to fix that by stacking a fractional ND filter on the colors that get more density? Presumably the issue is differing sensitivity for different frequencies which can be compensated with exposure. A densitometer and a few ND filter attempts should validate this -- basically you want to add ND to the color filter for the separation where the curves that come in higher to bring them to the lower one, and then adjust overall exposure times to get the desired density overall.

That's a fix for the different filter factors required for the RGB filters, resulting in different densities. The curves are above and below each other. Even then, within reason, this isn't even necessary as compensation can be made when exposing the seps. Another nice feature of Tmax is that the filter factors are roughly the same for the RGB filters. The problem I'm facing is the different curve slopes for each sep. It's not really a problem, because as I've described earlier, the standard procedure is to run tests to determine the required development times for each sep. I just don't like running tests. That's why Tmax 100 is such a godsend for making seps. Unfortunately, Tmax 100 is a problem for UV processes.

 

[nickandre]

That's a fix for the different filter factors required for the RGB filters, resulting in different densities. The curves are above and below each other. Even then, within reason, this isn't even necessary as compensation can be made when exposing the seps. Another nice feature of Tmax is that the filter factors are roughly the same for the RGB filters. The problem I'm facing is the different curve slopes for each sep. It's not really a problem, because as I've described earlier, the standard procedure is to run tests to determine the required development times for each sep. I just don't like running tests. That's why Tmax 100 is such a godsend for making seps. Unfortunately, Tmax 100 is a problem for UV processes.

I see -- so hypothetically with enough tests it's possible to match the curves for neutral grey? Or is there additional development work required to match the curves?

 

[ciocc]

I see -- so hypothetically with enough tests it's possible to match the curves for neutral grey? Or is there additional development work required to match the curves?

Correct. Neutral grey is the desired goal. Since I'm making my own pigment papers, a reasonable goal is something somewhat close to neutral gray. One popular procedure to determine the development times for each sep requires 16 sheets of film. 4x5 film isn't cheap. Tmax 100 eliminates all that work. I'm just hoping Tmax 400 behaves just like Tmax 100. Once you've done that test, you don't need to do it again. You end up with a gamma/development time curve for each filter that you consult for any condition you've photographed your subject under.

 

[Nicholas Lindan]

Neutral grey ... that can be a problem.

What can look like neutral grey under artificial light may not look like neutral grey under natural light. Compare your test print against a good grey card and in several lighting scenarios - you likely won't be able to get a perfect match under all conditions but you should be able to get a 'good enough' match.

 

[Lachlan Young]

I see -- so hypothetically with enough tests it's possible to match the curves for neutral grey? Or is there additional development work required to match the curves?

A lot also depends on the malleability of the particular CMY/ CMYK assemblage at the end - you mostly want to get 'neutral enough' without major cross-over & then pull the final adjustments in at the later stages of the process to land more-or-less where you should be going. The TMax 100 issue is really only a problem if you want to go from camera neg to carbon tissue etc in one step - if you are going from a transparency or colour neg, you've got more options as to how to go about it.

 

[DREW WILEY]

Matching all three film curves over their total distance can be tricky. It can be done with FP4 if you distinctly increase the contrast gamma during development of the blue separation versus the red and green separations. That was the case even with old Super-XX, the film choice of former times. With TMax 400 (current version), it is in my experience the G separation out of sync with the other two. And I've known of Delta 100 being digitally tweaked to create matching curves; but it certainly wouldn't be ideal for fully darkroom protocol. TMax100 is the only extant film which was originally engineered with color separations in mind, among other potential applications, and where all three separations can be developed together for the same amount of time to achieve matching curves, provided you learn the sweet spot of exposure. That characteristic saves a lot of work. It also has more cooperative spectral sensitivity to begin with.

So based on my own personal testing, which was rather thorough and fully densitometer plotted, YES, you can use TMY400 for high quality separations, but not with as much ease as TMX100. Another interesting option which some have taken for tricolor cameras, was to expose R&G with TMX100 film, but the B separation with TMY400 because the blue filter itself (47 or 47B) is denser and requires longer exposure otherwise. But in this case, you apparently want to use TMY400 for everything because the 100 speed product blocks a certain amount of UV. Whether that's a significant factor or not would require testing itself.

Remember, successful color separations mean attaining overlapping curves over the whole distance of scene luminance range. Merely matching midpoints won't hack it. It takes a lot of testing, plotting, an practice. And then you still have to tweak it for your intended print medium.

 

[ciocc]

A lot also depends on the malleability of the particular CMY/ CMYK assemblage at the end - you mostly want to get 'neutral enough' without major cross-over & then pull the final adjustments in at the later stages of the process to land more-or-less where you should be going. The TMax 100 issue is really only a problem if you want to go from camera neg to carbon tissue etc in one step - if you are going from a transparency or colour neg, you've got more options as to how to go about it.

"neutral enough" is all I'm going for. I'm a hobbyist, not a professional shooting for a client in the advertising industry. So accurate color rendition isn't necessary. Just want a reasonable copy of the subject, not something unrecognizable due to crazy colors. It's just a project, to see if I can make a color assembly print. I'm going direct from camera neg to pigment paper. I don't want to deal with masking, etc. It's hard enough as it is. Tmax 100 is the holy grail with respect to separations, it's just that it has that darn UV blocking layer. I'm just going to pay the money and get the box of Tmax 400 and find out for myself if the seps develop to the same contrast with a given development time. If they don't, I'm going to have to get off my lazy rear end and burn 16 sheets of film to find the correct development times for the seps. Balanced pigment papers is another issue, but I'm just going to ignore that and see what result I get.

 

[ciocc]

Matching all three film curves over their total distance can be tricky. It can be done with FP4 if you distinctly increase the contrast gamma during development of the blue separation versus the red and green separations. That was the case even with old Super-XX, the film choice of former times. With TMax 400 (current version), it is in my experience the G separation out of sync with the other two. And I've known of Delta 100 being digitally tweaked to create matching curves; but it certainly wouldn't be ideal for fully darkroom protocol. TMax100 is the only extant film which was originally engineered with color separations in mind, among other potential applications, and where all three separations can be developed together for the same amount of time to achieve matching curves, provided you learn the sweet spot of exposure. That characteristic saves a lot of work. It also has more cooperative spectral sensitivity to begin with.

So based on my own personal testing, which was rather thorough and fully densitometer plotted, YES, you can use TMY400 for high quality separations, but not with as much ease as TMX100. Another interesting option which some have taken for tricolor cameras, was to expose R&G with TMX100 film, but the B separation with TMY400 because the blue filter itself (47 or 47B) is denser and requires longer exposure otherwise. But in this case, you apparently want to use TMY400 for everything because the 100 speed product blocks a certain amount of UV. Whether that's a significant factor or not would require testing itself.

Remember, successful color separations mean attaining overlapping curves over the whole distance of scene luminance range. Merely matching midpoints won't hack it. It takes a lot of testing, plotting, an practice. And then you still have to tweak it for your intended print medium.

Thanks Drew, you've confirmed what I suspected. Tmax 100/3200 are the only Tmax films with matching contrast curves for the seps. Indeed it saves a lot of work. That's why I was hoping that Tmax 400 also shared that characteristic. As I wrote earlier, I may be able to use Tmax 100 after all. This is because my monochrome prints use negatives with a DR of about 2.0. The old literature on Carbon/Carbro states that a DR of 0.9 to 1.0 is all that is required for color work. This means a considerable reduction in my exposure times, which in theory should compensate for the 3 stop increase due to the UV blocking layer of Tmax 100. My monochrome negs print at 10 minutes. Tmax 100 would raise that to 1 hour and 20 minutes! I'd have to do that for 3 exposures. 4 hours total. Crazy. As mentioned, I'm a hobbyist, so accurate color rendition isn't all that important. Just want something recognizable with respect to the colors.

 

[dourbalistar]

Thanks for the mention @relistan! I'm even more amateur than @ciocc, but I appreciate it. In any case, it seems the resident experts like @DREW WILEY have chimed in here, but he also shared this info on a tricolor thread here on Photrio:
https://www.photrio.com/forum/threads/color-images-from-b-w-film.174977/

First of all, TMY100 was specifically engineered for this particular application in the first place (among numerous other features intended to replace several previous films). It has a very long straight line, correctly balanced spectral sensitivity, and is the only film I am aware of where, if one calibrates the 3 exposures correctly, is capable of having all three attain the same contrast gamma when developed together for the same length of time. A LOT of testing work and densitometer plotting has to go up front to learn to properly balance a set of negatives. Of course, on forums like this you're going to encounter plenty of fun stuff that isn't fussy in that regard, or else has been twisted and bludgeoned half to death via software to make the different separations sorta get along. But it is possible to do it well via totally darkroom workflow, just like it was routinely done countless thousands of times in the past when this was the routine mode of color reproduction. HP5 has none of the characteristics I described above. FP4 would work, but needs significantly more development of the blue exposure to match the gamma of red and green. With TMax 400, it's the green exposure that differs from the other two. I have a set of 8x10 filmholders right now loaded with TMX, and with precise filtration aperture settings listed on each, but just haven't run into the correct subject yet. It's been an unusually windy year around here, and obviously not an ideal travel year. But I do sometimes make color separations in the lab from color chrome film originals, where it can be very precisely done that way. More recently, I've made a number of single-color filter separations from 4x5 and 8x10 chrome originals for sake of black and white prints. I hope to print a couple of those tomorrow. Typical color separation filter sets would include 25 red, 47 blue, and 58 green. A more precise but slower exposing set of even deeper filters would be 29 red, 47B blue, and 61 green.

 

[ciocc]

Neutral grey ... that can be a problem.

What can look like neutral grey under artificial light may not look like neutral grey under natural light. Compare your test print against a good grey card and in several lighting scenarios - you likely won't be able to get a perfect match under all conditions but you should be able to get a 'good enough' match.

As you may have gathered, I'm an extremely lazy person. One of the most lazy people you'll meet. That's why I'm going to shoot my color subject in a "studio" environment with daylight balanced flash. I'll have control over the color temperature and it should be repeatable.