Pre flash

[Rip77]

I tested pre flash for a warmer look and it’s coming out purple. I can’t seem to get it warm.

F16 M45 Y35 .8s

 

[RalphLambrecht]

I tested pre flash for a warmer look and it’s coming out purple. I can’t seem to get it warm.

F16 M45 Y35 .8s

are you prefashing paper for awarmer look?

 

[halfaman]

Are you putting film in the carrier while preflashing? The photo you are printing or at least a piece of orange mask. Otherwise is extremely difficult or impossible, depending on the enlarger head, to get a warm tone.

 

[koraks]

Are you putting film in the carrier while preflashing? The photo you are printing or at least a piece of orange mask. Otherwise is extremely difficult or impossible, depending on the enlarger head, to get a warm tone.

The other way around! Without the orange mask, more blue and green light are passed through, which means you get more yellow and magenta dye formation. Note how RA4 paper fogged to white light turns red, orange and yellow tones. It can help to use a blank piece of C41 film as a mask just to keep the filter values more in the ballpark where you expect them to land. It's technically not always necessary, but it can make the process a little more intuitive.

Most of the time when I pre-flash I just slide a white diffusor filter in front of the lens while keeping the negative in place. This is technically speaking not optimal because you basically smudge out the entire image into the pre-flash exposure, but in practice it works just fine and it's an easy way to use a single enlarger for both exposures.

@Rip77 when pre-flashing color paper, you generally have to exaggerate the filter values greatly. If your main exposure is e.g. 40Y 40M and you want to shift the highlights significantly to yellow, dial in something like 60Y or 80Y. Also, you can't really judge the hue shift of the image as such by just printing a blank test strip. You really need to evaluate the impact of the pre-flash on the image itself, by combining both exposures (the main image + preflash) on the test strip. Note furthermore that at the point where density starts to build on a blank test strip (without the main/image exposure), the pre-flashed image will already have been shifted quite strongly.

Finally, just to get this straight: you need to realize that the flash exposure will affect the highlights only, and if it's really strong, part of the midtones. The rest of the tonal scale will be less affected or not at all. So you effectively introduce a color crossover - and of course you compress highlight contrast.

 

[halfaman]

The other way around! Without the orange mask, more blue and green light are passed through, which means you get more yellow and magenta dye formation. Note how RA4 paper fogged to white light turns red, orange and yellow tones.

True that the fogged paper is a very deep red or reddish black. Lesson learned!!

I only did preflash a couple of times to recover highlight detail, like in BW printing, so I was not looking for a tone change (don't like it).

 

[Rip77]

Are you putting film in the carrier while preflashing? The photo you are printing or at least a piece of orange mask. Otherwise is extremely difficult or impossible, depending on the enlarger head, to get a warm tone.

I’m putting a blank negative in the carrier. The proceeding with the pre flash. I only have one enlarger so after that I put it in a box and then wrap thay with a trash bag before second exposure.

 

[Rip77]

The other way around! Without the orange mask, more blue and green light are passed through, which means you get more yellow and magenta dye formation. Note how RA4 paper fogged to white light turns red, orange and yellow tones. It can help to use a blank piece of C41 film as a mask just to keep the filter values more in the ballpark where you expect them to land. It's technically not always necessary, but it can make the process a little more intuitive.

Most of the time when I pre-flash I just slide a white diffusor filter in front of the lens while keeping the negative in place. This is technically speaking not optimal because you basically smudge out the entire image into the pre-flash exposure, but in practice it works just fine and it's an easy way to use a single enlarger for both exposures.

@Rip77 when pre-flashing color paper, you generally have to exaggerate the filter values greatly. If your main exposure is e.g. 40Y 40M and you want to shift the highlights significantly to yellow, dial in something like 60Y or 80Y. Also, you can't really judge the hue shift of the image as such by just printing a blank test strip. You really need to evaluate the impact of the pre-flash on the image itself, by combining both exposures (the main image + preflash) on the test strip. Note furthermore that at the point where density starts to build on a blank test strip (without the main/image exposure), the pre-flashed image will already have been shifted quite strongly.

Finally, just to get this straight: you need to realize that the flash exposure will affect the highlights only, and if it's really strong, part of the midtones. The rest of the tonal scale will be less affected or not at all. So you effectively introduce a color crossover - and of course you compress highlight contrast.

yeah I will try to exaggerate more. I even did an exposure at like 85c and 40m because I read that somewhere. I usually don’t touch the Cyan. I’m just trying to get a warm look and struggling. Appreciate the response.