Graininess problem / palladium printing

[sudek]

In my palladium printing practice, I use FO and pd solution 1:1 and no restrainer, the paper is COT-320, room temperature is about 30 C and humidity is around 70%. I don’t know why it looks so grainy on the face (I don’t have it on the original image). To see if there would be any difference, I added one drop of hydrogen peroxide into the FO and later on also switched to different paper(Arches) with same operations. But the results are the same. Is it abnormal that it looks that way?

Thanks much in advance for any comments/suggestions.

Sudek

 

[Simon Howers]

Hi Sudek.
Nothing wrong with your materials, I regularly use the same without problems.
COT320 has quite a soft surface and it is easy to 'overbrush' the emulsion onto the surface. This can produce a grainy or mottled effect.
Try a glass spreading rod.

Simon

 

[Ian Leake]

I agree with Simon that it's unlikely to be a chemistry or paper problem (assuming you're using Ferric Oxalate #1 not #2), and that over-brushing is your most likely problem. But there's no need to switch to a glass rod - just refine your technique.

Too much sensitiser means you have to keep brushing after the paper surface has softened. Too little sensitiser means you have to brush harder to cover the required area. The wrong brush can introduce problems too.

How big is your print? How much sensitiser are you using? What kind of brush?

 

[Loris Medici]

Grainness could be due the negative; IIRC, sudek was using digital negatives. Unfortunately, this is not the right place to ask about them...

I concur with the previous comments; using too little or too much emulsion and/or overbrushing and/or using too much pressure when brusing will cause uneven and/or grainy - mottled results.

Regards,
Loris.

 

[jeffreyg]

In addition to the good advice above. Although I use pt & pd you might consider slightly pre-wetting the paper so that it is barely moist especially if you are in a very dry setting and also adding a few drops of distilled water to thin your emulsion. With digital negatives you might be getting reproduction of the inks dot pattern.

http://www.jeffreyglasser.com/

 

[baachitraka]

30°C room temperature: Are you in paradise?

 

[TheFlyingCamera]

Another thought - although the difference is subtle, COT320 does have two different sides. If you coat on the less smooth side to begin with, you will get a grittier print. I didn't notice what developer you are using - I found I got better results with Oxalic Acid as a developer than Citric Acid, the one normally provided in the kit.

 

[sudek]

Thanks so much for all the illuminations!!

To Ian:
It's FO#1 and "Magic Brush". It's a bit embarrassing to say,though,that it's a very small print(3.3X5 inches). The amount is 4:4(FOd). And does "large black borders" mean that the solution is more than sufficient? I used to have 5:5 for 4X5 but with large black borders,well,it looks large to me as I compared with the borders of the platinum prints on net. So later on I change the amount to 4:5(for 4X5). Is it right?

And I just examined the digital negative carefully. It looks suspicious and seems to be responsible for it too. I'll do some searching on it.


To baachitraka,
To be exact, it's 29°C.

To TheflyingCamera,
Thanks for the reminding. I noticed COT320 has two different sides and have coated always on the smooth one. I use Sodium Citrate as developer. I compared once with KO but the difference was very slight to me though.

 

[Ian Leake]

Small prints are nothing to be embarrassed about 8 drops total is probably in the right ball park. But rather than use a formulaic answer, I'd ask you how it feels when you're brushing.

Does it feel like you're having to work the brush to cover the area? Does it feel like all the sensitiser has dried but you're still trying to brush out to the edges of your print? If so then add a bit more sensitiser.

On the other hand, do you find that you've covered your print area, but you've still got pools of sensitiser on the surface? Once you've covered the print area, do you still see wet trails off the bristle edges as you brush? Once you've covered the print area are you still getting puddles of sensitiser at the edges? If so then you've got too much sensitiser.

Regarding the ratio of ferric oxalate to pt/pd solution. These should always be equal. So if you want to increase from 4+4 then go to 5+5. And to decrease go to 3+3. If you want finer control then mix up a few prints worth of sensitiser (e.g. 10+10) and then count out 7, 8 or 9 drops of this mixed solution.

Hope this help.

Ian.

 

[sudek]

Thanks much for the detailed explaination.

I remember when I used 5+5 for 4X5, I felt the way you decribed about too much sensitiser. And when coating two 4X5 at one time, the second coating would appear to have more sensitiser compared with the first one, if I use the same amount. I had cut to 4+4 for 4X5 and it was the way you decribed about not enough sensitiser. And if I use 4+5 for the first coating, 4+4 seems to be enough for the second one.

Sudek

 

[Ian Leake]

The amount of water in your brush is also a factor. Best practice is to keep your brush in a glass of clean water between coatings, and then to squeeze out the excess water just before you use it. That way your brush's water content should always be consistent, so your coatings shouldn't be influenced by this.