RE: Gum Calibration 3 (Dark Tricolor)

[Loris Medici <mail@loris.medici.name>]

Hi Marek,

28 Ekim 2008, Salı, 2:56 am tarihinde, Marek Matusz yazmış:
>
> Loris,
> I somehow missed your method of negative generation, double curve is not a
> way to go since you are likely to apply opposite curves. Yo ushould only
> apply one curve. On the other hand you are printing paper negatives so you
> have to love and embrace the artifacts!

I work in 16bit mode + increase texture in the print, after 3 layers the
imperfections are not that much obvious. I'm skeptical one could tell the
difference between single and double curves by just looking the finished
tricolor print...

I'm after a look between photography (form) and painting (color and
tonality); if it was too perfect (to the extent of confusing it with an
inkjet print), then the point of printing the image in gum bichromate
would be moot anyway - why not using inkjet printer then?

> Just by looking at your printed gray scale I would say you have your
> pigment density correct, your gum thickness  and your exposure correct.

Thanks, indeed I was coating a little bit on the thick side. I now got a
grab on coating thickness...

> I have to say I just love the texture that I see in the print. Perhaps
> this is what I am looking for to emulate fresson print. This random
> non-photoshop texture seems to be very appealing to me. Does your paper
> substarte contribute to this in a ddition to paper negative?

No, it's due to the paper negative + printer's dithering pattern when
printing grayscale negatives... I have prints made on same paper (Fabriano
Artistico) using colorized Pictorico negatives that are smooth as a baby's
butt (almost, in the context of gum printing) ;)

> Perhaps a little less exposure or longer development might shift you
> tonality a bit.
> What is your development time?

Oops! Forgot to add this bit of info: development is 3x10 minutes...

>  What is not quite Ok is the fact that you would need such a drastic curve
> to bring your negative to more or less correct DR.

I think the DR is correct. If not, I would get paper white much earlier.
Currently it's right where it should be (steps 100 - 101). See below about
the curve.

> DId you try to print
> your negative with just balck ink only if the printer allows it,
> especially if you can have matt ink which is universally carbon black and
> consistent from printer to printer.

No I didn't, but using black ink only would increase the texture. Besides,
to my knowing, my printer mainly uses matte black + diluted matte black
(light gray) for all inks grayscale prints. Since I'm using plain paper
profile (= very little ink), I don't think the added color inks - if any -
are making a considerable difference. The curve is smooth and has no
peculiarities in the shape (in parallel with previous experience with
colorized negatives).

Regards,
Loris.