U of S | Mailing List Archive | alt-photo-process-l | Re: Tricolor gum, order of layers

Re: Tricolor gum, order of layers


  • To: alt-photo-process-l@usask.ca
  • Subject: Re: Tricolor gum, order of layers
  • From: Keith Gerling <keith.gerling@gmail.com>
  • Date: Sun, 28 Sep 2008 10:28:54 -0500
  • Comments: "alt-photo-process mailing list"
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Loris,

Oil or no-oil on those negs?

Keith

On Sat, Sep 27, 2008 at 7:45 PM, Loris Medici <mail@loris.medici.name> wrote:
> After the 4th try, I decided to go back to my original practice of
> printing in the following sequence: Y, M and C. I had changed this order
> in favor of C, M and Y later because that seemed more logical. But since
> the yellow I prefer is semi-transparent, when printed last it gives the
> image an ugly haze, which lowers dmax and contrast. (The semi-opaque and
> opaque yellows are worse in this aspect.)
>
> Starting with the C layer seemed a better way of doing at first, since
> it's the most problem prone layer + (for those who register by eye,
> looking at the printed image) registration is easier. That way, I could
> discard / reject the print early if the cyan layer goes bad. (BTW, ease of
> registration wasn't an issue to me since I use semi-opaque paper
> negatives...)
>
> Now, because of my pigment choice + the fact that it seems more logical to
> start with the lightest color and finishing with the darkest, I think I'll
> do it in the Y M C order.
>
> See the first two layers here
> 1. Cyan: http://tinyurl.com/4z6zp2
> 2. Cyan + Magenta: http://tinyurl.com/3hyzhh
>
> I guess both layers have too much pigment for tricolor work.
>
> Since both the Cyan PB15:3 and the Magenta PV19 are intense pigments, it's
> very hard to squeeze very little (less than what I used for the sample
> above) pigment from the tubes (into 2.5ml gum, for a print size of
> 8,5x11"), I guess I will also have to prepare stock gum/pigment mixtures.
>
> Whew! Tricolor gum is much tougher than I thought...
>
> P.S. Dear Keith, the 18lbs translucent inkjet bond is wonderful for making
> paper negatives. Thanks much for suggesting it! The results are much much
> better compared to ordinary photocopier paper and the exposure times are
> much shorter too (by -1.5 stop, my current exposure time with UVBL bank
> and 10% ammonium dichromate is around 6:20).
>
>