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Photo Forum / Film Photography / Darkroom / July 2004Base colour of cross processed film? Fuji RAP/Astia 100
I know I shouldn't have an orange base but what should the colour be? Greyish? Or clear? Thanks Nick > I know I shouldn't have an orange base but what should the colour > be? Greyish? Or clear? Assuming this is an E-6 film cross processed in C-41, you should have the same clear base in unexposed areas that you'd have in fully burned out areas (like the 35 mm leader) as a positive transparency. Only B&W films have a gray base (which, I'm informed by someone who should know, is still a color in the anti-curl back coating or underneath the emulsion, not in the plastic material of the film base itself). Overall, though, base color is determined by the film type, not by the process.  SignatureI may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. >> I know I shouldn't have an orange base but what should the colour >> be? Greyish? Or clear? [quoted text clipped - 7 lines] > Overall, though, base color is determined by the film type, not by the > process. I was expecting perfectly clear base but it's not. The negatives seem good will see how they print. Nick >>> I know I shouldn't have an orange base but what should the colour >>>be? Greyish? Or clear? [quoted text clipped - 12 lines] > > Nick Define "cross processed." If you processed the film in B&W chemistry, you won't have bleached away the colloidal silver yellow filter layer (which normally protects the green- and red-sensitive layers from blue light exposure in the camera). If you processed in C-41, the bleach-fix or bleach step that removes the image silver should have also removed that filter layer. So, what color did you wind up with? C-41 films, of course, have the orange base, but that's the base color (i.e. it's under the emulsion and antihalation, or in the back coating, and designed not to wash out); slide films generally have a fully clear base. SignatureI may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. > Define "cross processed." If you processed the film in B&W chemistry, E-6 film in C-41 chemicals. Nick >>>> I know I shouldn't have an orange base but what should the >>>> colour [quoted text clipped - 26 lines] > antihalation, or in the back coating, and designed not to wash out); > slide films generally have a fully clear base. No, the orange color is the leftover color couplers (I think they are colorless on at least one of the layers) and act as a built in correction mask. Where the coupler forms a color there is no masking (for that layer) and where there is no color formed the leftover coupler leaves a color residue. Bert >>>>> I know I shouldn't have an orange base but what should the >>>>> colour [quoted text clipped - 33 lines] > >Bert Beat me to it. Right on the money. Robert Vervoordt, MFA > I was expecting perfectly clear base but it's not. The negatives seem good > will see how they print. The negatives are very grainy. Reminds me of 1980's 400 speed film but worse. OTOH the prints don't look that grainy. It sort of blends in. By chance the colour filtration came in at the intial starting point for the paper so I didn't have to waste any time getting that right. Nick >> I was expecting perfectly clear base but it's not. The negatives seem good >> will see how they print. [quoted text clipped - 3 lines] > chance the colour filtration came in at the intial starting point for the > paper so I didn't have to waste any time getting that right. Following up. The negatives may be TOO dense. I'm thinking the next test will be at 100 EI and not 50-) Nick > > I know I shouldn't have an orange base but what should the colour > > be? Greyish? Or clear? > [quoted text clipped - 6 lines] > Overall, though, base color is determined by the film type, not by the > process. The gray in 35mm film is NOT an anti halation coating. Rather it is a pigment in the support itself. Both back coating and under emulsion coatings are used for anti-halation purposes, the latter in most color films. These are decolorized by the sulfite in either developer or fixing bath. No color film uses a back coating other than the Rem-Jet coating used on Kodachrome and some older motion picture stocks. You can prove this easily by soaking some film in household bleach. This will completely remove all the gelatin from both sides of the film leaving only the support. The orange color in color negative film is not the support or a coating but rather the color couplers (dye formers). They are colored when in the unreacted state to provide an automatic color mask to correct the parasitic transmission of the dye. In effect they raise the minimum density. Usually, colored couplers exist in two layers of the emulsion. The coupler in image areas is converted to the appropriate color for that layer. A careful examination of the image under high magnification will show that the "base color" does not exist in highly colored portions of the image. The idea of using colored couplers for masking originated with Westly T. Hanson of the Kodak Research Laboratory sometime in the mid 1940's. Kodak's first chromogenic negative film, Kodacolor, did not have the couplers, it was introduced in a later version of Kodacolor and in Ektacolor. There is no way of removing the mask without also removing the dye image. This method of masking is never used on color reversal films, nor is anti-light-piping pigment in the support. All should have perfectly clear supports after processing. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > The gray in 35mm film is NOT an anti halation coating. > Rather it is a pigment in the support itself. You and Rowland Mowrey need to compare notes, so we can all get the same story. I just had it from Mowrey on photo.net (like literally a few days ago) that the gray color of B&W films is in the undercoating or back coating, not in the support; he claimed to have handled hundreds of samples of support material and all was completely clear. The way you tell it is the way I had understood it, too -- but in direct opposition to Mowrey's tale, and with his background, I have to give him some credibility. Perhaps the support is dyed before coating, but at a later stage than where he handled the samples... In any case, we all seem in agreement that no E-6 film should have a residual pigment, dye, or any other sort of color in areas that were either grossly overexposed (for normal reversal positives) or completely unexposed (when cross-processed in C-41). I'd be interested in what Nick has... SignatureI may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. Well all of mine have come out with a yellowish base. Maybe with a hint of brown. Have you tried cross-processing that Astia yet? Simon. > I know I shouldn't have an orange base but what should the colour > be? Greyish? Or clear? > > Thanks > Nick > Well all of mine have come out with a yellowish base. Maybe with a hint of > brown. > Have you tried cross-processing that Astia yet? Ya this morning. The film is drying. It's fairly clear but if you put a gun to my head I'd call it grey. It's not like frosted glass but it's not perfectly clear either. The very end of the leader is bluish and I guess the grey really has a mild blue tint to it. Nick > The very end of the leader is bluish and I guess the >grey really has a mild blue tint to it. Yes, you might get some sort of tint if you don't use a stop bath between the dev and bleach. Normal C-41 doesn't call for this but several Kodak pubs indicate a tinted base might happen without the stop on print film. That most likely goes for chrome film processed in C-41 also. Larry Hmm... this is interesting. I use a stop bath. I also use a pre-wash of warm water to get the film up to the right C-41 temperature. When I pour the pre-wash away it's VERY blue... (I'm talking about cross-processing Astia here). Simon. > > The very end of the leader is bluish and I guess the > >grey really has a mild blue tint to it. [quoted text clipped - 5 lines] > > Larry > Hmm... this is interesting. I use a stop bath. > I also use a pre-wash of warm water to get the film up to the right C-41 > temperature. When I pour the pre-wash away it's VERY blue... (I'm talking > about cross-processing Astia here). I didn't do a pre-wash. The exposed leader is deeply blue. Kind of nice in a way. Without the orange mask I'm not sure how to judge the negative colours but if it wasn't cross processed they'd look right. With me the film is putting out enough dye to make the stop change colour. So not only does it turn the developer but the stop is orange also. It's mostly C-41 film in the tank. Nick > I know I shouldn't have an orange base but what should the colour > be? Greyish? Or clear? > > Thanks > Nick It would make more sense if you process yourself to use E-6 color developer and simply skip the first developer and reversal bath steps. After all, E-6 color developer is going to be more suited to E-6 films. >It would make more sense if you process yourself to use E-6 color >developer and simply skip the first developer and reversal bath steps. >After all, E-6 color developer is going to be more suited to E-6 >films. I don't think this will work. The color developer I think is a fog type developer. Everything will have a fog if it works at all. Larry > >It would make more sense if you process yourself to use E-6 color > >developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 5 lines] > > Larry Worse than that I think. It will make all the halide developable so the film will come out black. If you bleach out the silver it will still be black since all the coupler will have been converted to dye. Remember that the dye is produced by a reaction of the coupler with developer reaction products. Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com >> >It would make more sense if you process yourself to use E-6 color >> >developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 11 lines] > Remember that the dye is produced by a reaction of the coupler with > developer reaction products. I glanced at a formula for the 1st E-6 developer. It looks like a B&W developer. Nick > I glanced at a formula for the 1st E-6 developer. It looks like a B&W >developer. CORRECT Larry > > >It would make more sense if you process yourself to use E-6 color > > >developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 15 lines] > Los Angeles, CA, USA > dickburk@ix.netcom.com No, I said OMIT the reversal bath! >>I know I shouldn't have an orange base but what should the colour >>be? Greyish? Or clear? [quoted text clipped - 6 lines] > After all, E-6 color developer is going to be more suited to E-6 > films. I think you mean to skip the first dev and *bleach* steps -- if you skip both developers, you'll get clear film base after the fix. SignatureI may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. > >>I know I shouldn't have an orange base but what should the colour > >>be? Greyish? Or clear? [quoted text clipped - 9 lines] > I think you mean to skip the first dev and *bleach* steps -- if you skip > both developers, you'll get clear film base after the fix. No, doesn't anybody understand? C41 is essentially E-6 after the revrsal bath... > > >>I know I shouldn't have an orange base but what should the colour > > >>be? Greyish? Or clear? [quoted text clipped - 11 lines] > > No, doesn't anybody understand? C41 is essentially E-6 after the revrsal bath... Its not quite the same. The second developer has a fogging agent in it which will make all silver halide on the film developable regardless of whether its been exposed or not. Here is how reversal color processes work. First step, a black and white silver image is developed in the three layers (some films have more layers). After the first development each layer has a silver image and the undeveloped halide. The color couplers are not converted to dye because the developer does not have the right components to react with the coupler to produce it. Second step in modern processing is the _second developer_. This developer differs from the first developer in that it has the following two items: 1, a fogging agent; 2, the right stuff to react with the couplers to produce dyes. After the second development _all_ the silver halide in the film is converted to metallic silver but a positive dye image also exists in the areas where the second development took place. The second developer is selective because no halide exists in the areas already developed into a negative by the first developer. As a result, the second developer, which includes the color formers, works only in the other areas, resulting in a positive image. The third step is the bleach or bleach fix. This converts the metallic silver back to a halide and removes it. This can be done in a single solution called "blix" or in separate bleacher and fixer. The bleaching bath and fixing bath do not affect the dye image. If one omits the first developer and uses the second developer the results will be the conversion to silver of _all_ the halide in the film AND all the dye. So, you will have a black image even if the film is subsequently treated in blix to remove the metallic silver image; the dye will remain. If the film is developed in the second developer it will result in development of all the silver at once because of the fogging agent. Where a fogging agent is not included in the second developer the film must be fogged with light between the two development stages. In black and white reversal processing the process is somewhat different because the final image is formed of metallic silver rather than dye. For B&W the film is developed in a normal developer, the the silver image is removed by a bleach that dissolves metallic silver but not the remaining halide. This leaves a positive image composed of halide. This halide is made developable by either fogging with light or by a fogging agent in the second developer. The result is a positive metallic silver image. In the case of color negative film the "base color" is NOT in the support but is, as I explained in an earlier post in this thread, due to the color couplers themselves being colored. The coupler not reacted to form image dye remains its original color which is chosen to be a masking color to correct the transmission faults of the dye. These colored couplers are not used in color reversal materials. They can have an overall color cast due to processing problems like contamination. Neither does the support of either color negative or color reversal film have any pigment in it, its perfectly clear as one can demonstrate by removing all the gelatin, emulsion and backcoating, in a bath of household bleach. Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > > > >>I know I shouldn't have an orange base but what should the colour > > > >>be? Greyish? Or clear? [quoted text clipped - 15 lines] > in it which will make all silver halide on the film developable > regardless of whether its been exposed or not. No, it doesn't. That's the Reversal Bath, step 2, which I say to SKIP. Kodak E-6 Color developer does not have a reversal chemistry in it. Perhaps Tetenal or other chemistries do, but not Kodak. http://www.kodak.com/global/en/professional/support/techPubs/j83/j83.jhtml?id=0. 1.16.14.30.14.3.26.3&lc=en Solution/Step Time1 (min:sec) Temperature°C (°F) Comments Lower Limit Aim Upper Limit Perform these steps in total darkness. First Developer2 5:00 6:00 7:00 36.7 to 39.4 (98 to 103) Recirculate and filter. Nitrogen agitation.3 First Wash 1:00 2:00 4:00 33.3 to 39.4 (92 to 103) Air agitation.3 Reversal Bath 1:00 2:00 4:00 24 to 39.4 (75 to 103) Recirculate and filter at startup.4 No agitation. Remaining steps can be done in room light. Color Developer 5:00 6:00 7:00 36.7 to 39.4 (98 to 103) Recirculate and filter. Nitrogen agitation.3 Pre-Bleach 2:00 2:00 4:00 2 to 39.4 (75 to 103) Recirculate and filter at startup.3 No agitation. Bleach 6:00 6:00 8:00 33.3 to 39.4 (92 to 103) Recirculate and filter. Air agitation.3 Fixer 4:00 4:00 6:00 33.3 to 39.4 (92 to 103) Recirculate and filter. Air agitation.3 Wash5 2:00 2:00 4:00 33.3 to 39.4 (92 to 103) Air agitation.3 Wash5 2:00 2:00 4:00 33.3 to 39.4 (92 to 103) Air agitation.3 Final Rinse 0:30 1:00 4:00 Ambient No agitation. Dry As needed Not above 63 (145) -- >>>It would make more sense if you process yourself to use E-6 color >>>developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 5 lines] > > No, doesn't anybody understand? C41 is essentially E-6 after the revrsal bath... Ah, okay, my mistake -- I was forgetting the differences between E-4 and E-6 (I did E-4 about 30 years ago, but I've never done E-6). I was thinking E-6 used a fogging color developer (like a B&W reversal process), but in fact with standard E-6 it's a separate fogging bath to ensure the color developer can develop all the silver the first dev didn't; only the three-bath version combines reversal and color dev. The only advantage I can see to processing in the post-reversal part of E-6, instead of C-41, is that the E-6 dyes might be a better match for the original emulsion sensitivity curves -- which would be fine if you wanted straight negatives from your E-6 film, but makes little sense if you're after the "cross processed" look of slightly shifted color balance and altered saturation. And of course your method can't be used with a three-bath E-6, only with the longer process that doesn't combine steps. SignatureI may be a scwewy wabbit, but I'm not going to Alcatwaz! -- E. J. Fudd, 1954 Donald Qualls, aka The Silent Observer Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. > >>>It would make more sense if you process yourself to use E-6 color > >>>developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 19 lines] > you're after the "cross processed" look of slightly shifted color > balance and altered saturation. But the main thing is that the color masking is absent. It should provide a better result than C41. Why doesn't someone compare the two? And indeed, E-4 DID have a fogging color developer. I used to run some E-4 myself. > And of course your method can't be used with a three-bath E-6, only with > the longer process that doesn't combine steps. >>>>It would make more sense if you process yourself to use E-6 color >>>>developer and simply skip the first developer and reversal bath steps. [quoted text clipped - 22 lines] >And of course your method can't be used with a three-bath E-6, only with >the longer process that doesn't combine steps. Yes, your correction is,... correct. Yet, something is being missed in this discussion. The E6 films will have a Yellow filter layer between the first and lower layers. This is made of finely deposited silver and its purpose is to remove Blue light from reaching the lower layers, which have some Blue sensitivity. In E6 first development this layer is removed by a Silver solvent similar to Thiocyanate. This is not present in C41 developer or E6 color developer. Therefore, the resulting image will have this silver layer, which may not show up as Yellow in all cases. Its color may be affected by the subsequent C41 baths, resulting in Gray or Blueish base tints and a slight increse in base density. This might be dependent on the original emulsion used in the camera. One other minor point, the composition of the E6 first developer would generate some the dye image if there were as little Sulfite as in C41. I did this at least once in compounding a B&W developer for C41 speed boosting and messed up an E6 roll that I put through the process to see what would happen. If you were to add Sulfite to a C41 developer and use it for any color emulsion as the only developer, you will get almost no color. About 40 grams will leave the film blank, My suggestion is to add some Silver halide solvent, at around the same proportion as in E6 first developer, to the color developer formula you are using in order to clear the lower densities of halide. There are other considerations that could be affecting the final image, but I suspect they are not significant. One such is the Iodide restrainer in the E6 first developer, which affects the topmost layers more than the lower ones in permitting the action of the Halide solvent to be controlled. Robert Vervoordt, MFA > >>I know I shouldn't have an orange base but what should the colour > >>be? Greyish? Or clear? [quoted text clipped - 9 lines] > I think you mean to skip the first dev and *bleach* steps -- if you skip > both developers, you'll get clear film base after the fix. No, no, no: http://www.kodak.com/global/en/professional/support/techPubs/j83/j83.jhtml?id=0. 1.16.14.30.14.3.26.3&lc=en Read the steps following the statement: 'Remaining steps can be done in room light.' |
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