Topic: colour question

[formica]

as most of you know, i recently tried my hand at processing colour film in bw chemicals. nearly the entire roll came out all purple. except for 3 or 4 pictures(see some examples below plus one of the purple shots). i wish more of the roll would have come out with this more brownish colour shift. any ideas why only a few shots came out this way? just a quirk of the processing? processing too long or not long enough? my sister mentioned that maybe bleach could lessen the purple cast - has anyone tried it?

        william

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[Francois]

When you look at the negatives (in negative), is the base evenly colored?

The shift might be an artifact of the scanning software.

[seekingfocus]

Well, I have no idea about your question, but personally I don't mind that color shift at all. Rather reminds me of a cyanotype image.

Also, is the idea behind these to scan them, or ultimately to wet print them? In the case of printing, it seems either would likely print adequately. If scanning, the color shift could likely be corrected in post-processing... Just a thought.

-Jason

[formica]

When you look at the negatives (in negative), is the base evenly colored?

The shift might be an artifact of the scanning software.

i thought that too. looking at the negs they are different than the rest of the roll. most of the images are very dense. some were even quite hard to scan as it was hard to see where to highlight them to adjust before scanning, but a a few are closer to being normal which were these. i wonder if this might mean if i do this again i should process for longer? i accidentally diluted the developer a little more than i should have when i did this roll.

 jason, this was just an experiment. i'm not sure how easy it would be to wet print these as the negs are very dense. of course having said that i might ask a lab to try to print one of them and see what they get.  colour correcting is an option, but it's something i usually don't care to do.

                        william

[Francois]

The color cast might very well foul the scanning software. I know it happens from time to time with Epson Scan. I then have to manually adjust the histogram and everything.

I do find it odd that the cast is uneven. The orange mask is the same throughout the film... though it could be something related to the seird effect I found on apug where the guy managed to see colors in the negative by playing with the scanner settings. The same thing might be going on...

Did you pre-wash the film with a water bath?
Might be the anti halation layer which is still partly stuck to the film... (though I doubt it)

[formica]

The color cast might very well foul the scanning software. I know it happens from time to time with Epson Scan. I then have to manually adjust the histogram and everything.

I do find it odd that the cast is uneven. The orange mask is the same throughout the film... though it could be something related to the seird effect I found on apug where the guy managed to see colors in the negative by playing with the scanner settings. The same thing might be going on...

Did you pre-wash the film with a water bath?
Might be the anti halation layer which is still partly stuck to the film... (though I doubt it)

i wouldn't rule out the scanner being part of the issue. i didn't prewash as it seems like i'd read somewhere that that wasn't neccesary with colour film. i'll probably try this again at some point and pre-wash that roll.

                    william

[LT]

Might be the anti halation layer which is still partly stuck to the film... (though I doubt it)

these are 35mm arent they?  does colour 35mm have a washable antiH layer like 120 b&W?  I know 35mm B&W has a dye inside the base to stop halation, so that's not washable (why 35mm always has a darker base than 120 unless you're using HIE or Lucky)

[formica]

these are 35mm arent they?  does colour 35mm have a washable antiH layer like 120 b&W?  I know 35mm B&W has a dye inside the base to stop halation, so that's not washable (why 35mm always has a darker base than 120 unless you're using HIE or Lucky)

yes, it's 35mm. i suspect it may not have a washable layer based on what i'd read about developing colour negs. someone around here should know for sure.  i always prewash my bw 35mm when i develop it myself. is this unnecessary?

               william

[Francois]

I know there is a dark red layer that is used in color negatives...
The layer is placed first on the emulsion when it gets coated. This layer is the only one which needs an anti halation layer since all the other layers get filtered. It would make sense to me that this layer be red... though I'm not a chemist in any sense.

That's why it is possible to do a process they call Redscale which is probably enough to scare the living daylights out of the photolab tech

The orange mask (the base) is used to reduce contrast in the printing process. Since contrast goes up a notch for every step the image is duplicated, this is necessary.

To compare what a mask-less base would do, just look at cross processed E-6 slide film.

For fun trivia, undeveloped color RA-4 paper is robins egg blue on the emulsion side (opposite of the orange mask). I learned that from an old time photo tech, the rolls of paper in the machine are longer than what the company makes. So every so many meters, the paper manufacturer has to splice the paper by making a 45 degree cut and putting a type of tape on the seam. When the machine reaches this point, it skips a length of paper and keeps on printing. Since the seam is protected by the tape, it doesn't get developed. When you pull on the tape, it's a nice baby blue underneath.

[LT]

.  i always prewash my bw 35mm when i develop it myself. is this unnecessary?
               william

that would depend on who you ask.  I also do it with water at the same temperature of the developer I'm going to use, so there are no shocks when the developer is poured in.  Others say not to do it as some manufacturers include development chemicals on the film which you are effectivel washing away.

SO Francois, still not clear - are you saying there is a washable layer in colour film?  I dont really do colour, so this is just for my info ... I might ask someone to get a definitive ... will report back.

[Francois]

I'll be waiting for the answer since I too am not definitely sure about it...

As for pre-wash, it's worth doing for B&W since it avoids creating air bells on your film. It also evens out development.

I've never heard of developing agents being layered directly on film. If that's the case, I wonder why there never has been an activation type film (like the old Ilford Multigrade III paper which was activation compatible)...

[LT]

well - the answer to whether the Anti H layer is as per 35mm mono films question is: yes and no - it all depends on the manufacturer - some have a washable layer, some dont. 

Francois - this may be one of those myths and rumours that abound in film production etc.  It's something the late Barry Thornton told me in response to a query I had over problematic development of Fuji Acros in his Exactol developer.

[Francois]

I figured out as much...

I tried putting a color film leader in about 1/4 oz of water to see if anything would come off. Water was just as clear as before. Probably would have changed with more film and water... though it might be a very limited change. The emulsion side did become somewhat lighter when wet. I'll have to wait until tomorrow to see if the change is permanent (reaction or dilution of something with the water).

[al]

It does depend on the manufacturer.  I usually pre-soak colour films before developing as an easy way to get the film/tank up to temperature.  With kodak films, the pre soak water often comes out very dark green

[LT]

yes Al - that's the anti halation dye coming out - most black and white films have these (ilford inky black/blue, kodak greeny, fuji lighter blue etc., but most 35mm black and white films have it as a non-removable dye inside the film base - that's why they have a darker/ denser base than 120 films which usually clear entirely. Just not clear abotu how this works with colour 35mm, but at would appear that it all depends (as is usually the case!)

[formica]

so if you don't pre-soak could this be contributing to how dense the negs are when they are processed in bw chemistry?

                         william

[Francois]

I really doubt it, the AH should come off during the developing process which basically "washes" the film while it gets developed.