Colin that's nice - thanks for the trouble. I find myself often upping the saturation for RGB separations. And let me tell you: it works! All depends on your pigments and pigment saturation... I don't think there's an absolute correct way of doing it; depends on your materials / work flow and (ALSO) image / purposes...
Regards,
Loris.
Colin that's nice - thanks for the trouble. I find myself often upping the saturation for RGB separations. And let me tell you: it works! All depends on your pigments and pigment saturation... I don't think there's an absolute correct way of doing it; depends on your materials / work flow and (ALSO) image / purposes...
Regards,
Loris.
Dave,
How are you registering the print once it's bonded to the aluminum?
So if i read you correctly Rob, i could lay down a size such as PVA after say a second gum coating whilst still having the print attached to aluminium? I like having the ability to avoid registration issues that bonding to aluminium provides especially as i would like to eventually like to print quite large gum prints in addition it seems so much easier get a good coat down whilst its attached to a flat surface.
thanks
Will definitely try upping the saturations in the next couple of prints to see what happens, thanks for that. What digital negative creation method are you uisng Loris?
Here's one I did a +75 saturation, just had to see... Plain RGB on bottom.
Here's the original file, sorry I should have thought to include that for reference. I think a final cyan pass might calm the wild colors down a little, so a saturation boost of 35-40 or so could come out pretty close to the original. Greens especially seem to need more boost. The +75 saturation version is 3 pass; cyanotype, PV19 and PY97. The regular RGB version had that plus a final cyan pass.
Thanks again for your contributions to this thread Loris, really opened some new doors up as well as solved some nagging old problems.
A note: Depending on your pigments, you may need different saturation boost amounts for different channels; e.g. for nicer greens I would leave the R channel (C layer w/ cyanotype) w/o saturation boost and fiddle with the B channel (Y layer) instead... (But that depends also on your Y pigment!)
Just play a little bit, and you'll come to an understanding of your materials and how they interact as a whole system. Since my aim (with gum) is never to exactly replicate what I see on screen, I can't help further; I just haven't done any balancing equations / tests with Ol No Moir (or similar) file, and don't plan to do it in a predictable future...
Regards,
Loris.
Did i read that right, can you do another layer of cyanotype at the end? That would be great if you could do that.
Yes, I did use a final cyanotype pass- it was actually the first time I've ever tried it so I'm not sure how reliable it is, but it worked great in this instance.
With some renewed energy I wanted to try and get my cyan-gum prints working. As before i am still having problems with the magenta layer. As people suggested I started using the colour ole file to calibrate. The attached image is the cyan and the yellow layer. Am i nearly there to what you should be getting at this stage?
This is even without bonding to aluminium, so at the moment i might forego that stage and try and size the paper to see if that helps my M layer proplems. Can I use any PVA glue or does it have to have a specfic type of PVA? Can I size after the cyanotype and magenta layer? I have seen nerchau caparol binder used, might that be better?
I have also attached a scan of just the magenta layer (PV19), this is on Fab Art (acidified) Clearly I need to try a new method of getting this M layer down.
thanks
The attached image is the cyan and the yellow layer. Am i nearly there to what you should be getting at this stage?
thanks
I haven't worked with the ole no moire file, but for color fidelity work it helped me to print the positive separations in aggregate combinations with my printer to see how close I was getting with my gum pigment layers. I print cyanotype-y-m so I printed out the cyan positive, then the cyan + yellow and finally the full file c+y+m. Made for a nice roadmap while I was profiling curves and pigment concentrations and trying to get my head around how the colors combine.
Dave,
1) The Yellow pig over Cyan looks about right on my monitor but you won't really know until you have printed the Magenta layer to see the final color balance.
2) What Magenta are you using? I know you listed PV19 but is that Quinacridone Violet or Quinacridone Rose. You may need to try several different brands. If possible try M. Graham Q. Rose. The M. G. watercolors use honey as part of the binder and that seems to make a big difference with some colors.
3) Also use as little mag. pig as possible and coat thinly and expose carefully, Over exposure with the Magenta can be very problematic for development. One of the best solutions for slightly over developed magenta layers is to perform some physical development with a spray bottle that can atomize (a very fine mist) the water spray. Use warm water to.
4) Another key to improving the magenta layer results is to use a blending brush to smooth the layer as the final step in coating.
5) Do you have the Ole Moire with the color patches? I find that one is a good test image also.
I think it is fair to say that many people come to tri-color gum thinking that the process will be a rote process. The truth is that it is anything but that, at least in the darkrooms of individual photographers like us working outside the rhealm of manufacturered media.
Don
I haven't worked with the ole no moire file, but for color fidelity work it helped me to print the positive separations in aggregate combinations with my printer to see how close I was getting with my gum pigment layers. I print cyanotype-y-m so I printed out the cyan positive, then the cyan + yellow and finally the full file c+y+m. Made for a nice roadmap while I was profiling curves and pigment concentrations and trying to get my head around how the colors combine.
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