Flocculation and Gum prints

[Colin Graham]

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.

That's very true, Loris. I notice the cmyk version tends to sacrifice depth and dimensionality in favor of saturation, so it's definitely not a cure-all. It's fun to play around with though. I'm still looking for a good compromise between RGB and CMYK. Thanks for the boost saturation suggestion, I will try that out for sure.

 

[Davec101]

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.

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?

 

[PVia]

Dave,

How are you registering the print once it's bonded to the aluminum?

 

[Davec101]

Dave,

How are you registering the print once it's bonded to the aluminum?

Pin registration, its simple and it seems to be working a treat at the moment.

 

[R Shaffer]

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

Yes. You could brush size with gelatin as well if your going for the more classic approach.

I like the Gamblin PVA Size diluted 1:1 with water because it is just plain easy. I brush it on a dry print with a foam brush. I used to smooth it out with a foam roller after, but I don't see any difference so I'm just brushing it on. It dries quickly compared to gelatin.

It will speed up your development time, at least it does for me. So keep a keen eye on your print.

I learned about it on "The List" and one of the guys actually posted a youtube video on it, but I can't find the link to it. There is a long discussion on it there as well.

Dead Link Removed

 

[Loris Medici]

Dave, Colin - that's a trick I've learnt from / hinted by Keith Gerling. I'm sure you'll get better results (not necessarily exactly what you want, though!) doing so...

I use my own system (curve calculator) derived (the idea) from PDN v1. (I still use the PDN colors, but a different / self-made curve calculator. I choose / opted for OpenOffice.org Spreadsheet, which has a superior b-spline smoothing / trend-line algorithm...)

Regards,
Loris.

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?

 

[Colin Graham]

And a good trick it is- I got much punchier colors upping the saturation just 25%. I'd forgotten that I messed around with this a little last year, but had so much else going wrong at that time I couldn't notice the improvement through the other unrelated disasters..

 

[Colin Graham]

Here's one I did a +75 saturation, just had to see... Plain RGB on bottom.

 

[Loris Medici]

Wow, you're a real hard working ant Colin! Thanks much for the visuals - they are going to be very useful for future readers of this thread.

Regards,
Loris.

 

[Davec101]

Here's one I did a +75 saturation, just had to see... Plain RGB on bottom.

Looks good, i have printed out some new negs with +25 sat, hopefully will get a chance to print them out in the next few days.

 

[PVia]

Colin, what was the original like? Was it closer to the ultra-saturated gum or the plain RGB?

 

[Colin Graham]

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.

 

[Davec101]

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.

Did i read that right, can you do another layer of cyanotype at the end? That would be great if you could do that.

 

[Loris Medici]

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.

 

[Davec101]

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.

Loris, how do you actually increase saturation in each of the channels? the three channels i have i.e CMY are all converted into grayscale and thus saturation cannot be changed.

 

[Loris Medici]

Hi Dave,

I duplicate the original RGB file, increase the saturation and split the channels. I then discard the R channel (C layer) of this duplicate file, split the channels of the original file and discard the G and B channels. I then end up with the extra-saturated G (M) and B (Y) channels of the duplicate and the non-extra-saturated R (C) channel of the original...

Regards,
Loris.

 

[Colin Graham]

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.

 

[Davec101]

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

 

[donbga]

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

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

 

[Colin Graham]

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.

 

[donbga]

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.

That's a very interesting approach Colin.

So when you print the C+Y and C+Y+M positive are those seps just layered together and then printed? Or do you print the each color layer separately and run the media back through the printer printing the next color sep. ?

If anyone wants the Ole files PM me and I can sent them to you all. Please include your e-mail address and I can send them through my you sent it account.

Don

 

[Colin Graham]

Don, I just delete the channels I want to exclude in each printing, straight from the RGB file. The solo cyan layer positive (or any other single channel) will look like a grayscale image in PS, and the print preview won't look right at all, but the correct cyan info does seem to get sent to the printer driver.

I use printer managed colors, not PS management, because I've been proofing on art paper and need the driver saturation controls to reduce dot gain and get the saturation right. But it seems like it should work with PS management/ regular inkjet paper profiles...But for really critical color work some serious profiling and calibration would be in order.

 

[Colin Graham]

Here's what it looks like on some cheap Epson glossy-

 

[Davec101]

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

As always thanks Don for taking time to reply and making suggestions, much appriciated. The Magenta I am using Permanent Rose (PV19). I have increased the dichromate to gum ratio, which seems to help a little. When you do this what does it actually do, also vice-versa having a higher gum to dicromate ratio?

I have attached a scan of the final result of cyan-gum print test print. I am quite out at the moment and there is still little traces of fish eyes in Ole face. I will just have to keep trying various methods and different reds, i might try and move the magenta layer to the second coat rather than the last. If you could email me the ole file with colour patches that would be helpful. many thanks (davidchow2002@hotmail.com)

 

[Davec101]

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.

This was such a great idea, I should have thought about doing it earlier!

I printed the CMY layers individually on transparency film and then cut them out and layer them on top of each other and placed on white paper, works a treat (see attached). A really good way of seeing how the process works for those starting out gum printing.