U of S | Mailing List Archive | alt-photo-process-l | Re: How many gum layers (Re: ferri sesquichlorati)

Re: How many gum layers (Re: ferri sesquichlorati)

And this... :-)


I did gum printing about 10 yrs ago and this is roughly the way I did it
then, except I used "normal" silver negs. Assumed since then that this is
the way one does gum. Did first come across the pigment adjustment method
recently & got a bit confused.

Pigment description is from : Wall, E. J., Jordan, F. I. Carroll, J. S. ed.
Photographic Facts and Formulas. Prentice­Hall and Amphoto. 1975. pp 313-14.

Both methods seems to give more or less straight curves, when you cut of the

(Found the rest of that book very interesting, the "pepper dusting on
process" has to be tried some day :-)

And the best description I have seen so far of the fresson process.)

I think I quietly back out of the rest of this debate :-)

On 10/25/06 12:51 AM, "Kees Brandenburg" <ctb@zeelandnet.nl> wrote:

> Hi Halvor,
> For me the first method works best. I try to make negatives that fit
> carefully with the short scale of gum. The most important is to
> transfer all information in the original image to this negative
> (digital or analog the same). This does not mean information gets
> lost, it's only distributed à la gum. When printed with the first
> gumlayer and with the ideal printing time that gives  the first
> maximum shadow density I print for the transfer of all image
> information. When looking at this one layer gumprint all  image
> details shoulkd be there in all their delicacy. But this 'perfect'
> layer is still looking a bit transparant and  much to weak in shadows
> and midtones. Only the lightest part of the image is ok.
> I then try to print extra layers with exactly the same gum/dichromat
> and pigment concentration (and sensitivity) while shortening printing
> time for each layer. This adds density in shadows and midtones and
> makes the straight part of the curve tilt upwards to get more
> contrast. A final extra punch can be added by a black or other dark
> layer with an extremely short printing time.
> When printing too much layers sometimes density gets lost in the
> highlights by abrasion. That's the only moment when I sometimes print
> an extra layer with less pigment. But still the same gum/dichromat
> ratio.
> kees