Autochrome RA-4 Reversal attempts

[ThePhotoChemist]

Hey everyone!

RA-4 reversal has always interested me, and I thought it might be a fun way to make "prints" of my autochromes. I had a secondary idea too, involving exposing a blank autochrome screen-plate in front of RA-4 paper in camera, to make a sort of faux-autochrome print.

I have yet to try the second idea, but my first tests with making prints didn't pan out so well. I tried a variety of filtration with yellow and magenta filters from a Cibachrome printing kit, but I was never quite able to get the color "blue"... Even when the rest of the colors were balanced and whites were mostly neutral looking, blues always kind of came out grey.

In the autochromes, additive colors of violet and green make the color blue. But for some reason, this doesn't seem to quite translate as well when remade into a subtractive color system. I wonder if RA-4 paper is even equipped to handle "violet" (e.g. does color film turn violet into purple, a mix of red/blue)?

Anyway, it was an interested experiment. I'd still like to follow up with in-camera tests with a screen-plate to see if that fares any better.

 

[Donald Qualls]

An alternative suggestion: if you have a filter pack that lets you make direct reversal RA-4 prints with true color, you could try rephotographing the Autochrome plate with that filter pack? From what I recall, some have had good results with a combination of 0 and 00 Ilford contrast filters (for B&W multi-grade papers).

 

[Snowfire]

Autochrome used a very strange basis set for an additive scheme--orange and violet rather than the usual red and blue. The normal subtractive colors are magenta, cyan and yellow. An equivalent subtractive set for the Autochrome system would contain magenta (the complement to green) but then also cyan-blue(the complement to orange) and yellow-green (the complement to violet.) If you try printing an original based on the OGV basis set onto material designed for the more conventional RGB/CMY system, wacky things may well happen, as the dye colors do not match.

 

[Marja]

Hey everyone!

RA-4 reversal has always interested me, and I thought it might be a fun way to make "prints" of my autochromes. I had a secondary idea too, involving exposing a blank autochrome screen-plate in front of RA-4 paper in camera, to make a sort of faux-autochrome print.

I have yet to try the second idea, but my first tests with making prints didn't pan out so well. I tried a variety of filtration with yellow and magenta filters from a Cibachrome printing kit, but I was never quite able to get the color "blue"... Even when the rest of the colors were balanced and whites were mostly neutral looking, blues always kind of came out grey.

In the autochromes, additive colors of violet and green make the color blue. But for some reason, this doesn't seem to quite translate as well when remade into a subtractive color system. I wonder if RA-4 paper is even equipped to handle "violet" (e.g. does color film turn violet into purple, a mix of red/blue)?

Anyway, it was an interested experiment. I'd still like to follow up with in-camera tests with a screen-plate to see if that fares any better.

Hi, the last picture you posted - can you remember what kind of filters you used? Like how many magenta, yellow ...? I am very curious.... thx!

 

[ThePhotoChemist]

Hi, the last picture you posted - can you remember what kind of filters you used? Like how many magenta, yellow ...? I am very curious.... thx!

Hey Marja! That was the actual autochrome I was using to try and make copies of.
A lot of the batches of plates I make tend to be oversensitive to blue and green, so usually during exposure I'm using something like a 30Y and 20M, but it varies a lot. This one is quite old, so I'm not sure what it was using exactly.