I have been starting to print pd on Fabriano Artistico Extra White 140 lb hot press. I am going to print gum eventually so that is the reason for this paper choice.
I have been told that I need to acidify the paper and was given instructions to do so in 4% oxalic acid for 15 minutes. I was told I could do multiple sheets at one time as long as I rotate them.
I have been doing so - the printing is working - but when I first coat with pd I get a mottled appearance - looks almost like age spots - some darker spots that seem to take up more pd. I dont know if it is related but when I print a greyscale image not all the squares of the same level read the same on the print.
In other words - a 20% square may read 18% in one square but 25% in another 20% square.
I was wondering if some one could tell me that is the norm for this paper or am I doing something incorrect in my process
thank you
Sean

Could it be the sizing has broken down in spots? I had the same mottled look with Arches Aquarelle when I held the sheets wet from the acid bath (5 minutes in 5% citric acid in my case) up to a light, and the emulsion really soaked in fast. I thought I had ruined the paper and was all set to resize, but they printed great.

I have been told that I need to acidify the paper and was given instructions to do so in 4% oxalic acid for 15 minutes. I was told I could do multiple sheets at one time as long as I rotate them.


Hi Sean, I've printed quite a bit on Artistico for platinum and I'm thinking that maybe your oxalic soak is too long. You may want to try a 2% for only 2-4 minutes in about 70 - 80 degree water. I'm thinking you may have dissolved the surface size unevenly from your 15 minutes in the 4% and this may be causing your 'blotchiness' I do agree that constant agitation in the oxalic is a good thing. Also, when I insert the Artistico I have noticed the surface size (which is heavy for this paper because it was created for water color) shows a type of uneveness as it tries to absorb the solution. I slide it in and do a few 'hard' tray rocks before the next sheet goes in and rotate constantly.

Best - Stan

Hi Stan

Do you wash after the oxalic, or just dry and coat?

Thanks, Ben

Hi Ben, I just let it dry naturally and coat, the 2% primes the paper well. It’s good though to change out the oxalic from time to time; it works pretty hard de-buffering and breaking down the surface size. I usually mix a new gallon after about 20 11 X 14” pieces. After you tape down your paper for coating it’s a good thing to brush the paper well before laying down the emulsion – some of the crud you can’t see from the oxalic bath can adhere to paper fibers and show up as a black dot after exposing. I usually take a paper towel roll and drag it down the paper a few times as if it were a silkscreen squeegee.

Stan

Thanks, Stan! I love the paper, but have not so far had a good m/o. I've moused around forums for info, but your method sounds like it's better worked-out than anything I found. This will save me some learning the hard way.

By the way, which side do you prefer? I've tried both.

Best, Ben

Hey Ben, I prefer the back. The front has very thin parallel lines closely spaced together that can be seen upon close inspection with the finished print. The back has a nice random pattern that looks great.

BTW, Artistico responds well to induced humidity, you may want to try a sheet w/ no humidity and one w/ about 83% (for comparison) humidify about 15 minutes after coating before exposing, lay down a sheet of Mylar/plastic on your exposure bed to lock in the humidity during exposure – in other words, make a Mylar, print with negative and glass sheet of vacuum frame - sandwich, this will keep the humidity locked in for exposure.

Stan

Hi Stan,

Yeah, I'd noticed those thin lines - I'm glad you are seeing them too, so it's not an artifact of my diginegs. I'm "between darkrooms" right now, the old one was temporary/improvised and had little humidity control, so I was humidifying the paper before coating. I'd noticed some pretty radical color effects which I had assumed were humidity variations. (I'm using POP Pd/Pt.) Should be fun to explore once I get up and running again - maybe there's a way to vary the look of different parts of the print... Thanks for sharing your expertise!

Ben

I'm "between darkrooms" right now, the old one was temporary/improvised and had little humidity control, so I was humidifying the paper before coating.

Just a thought, it would probably be worth the time to try and control your darkroom humidity at around 25 - 35% and make a humidity box for your induced humidity. This kind of standardization really pays off for control in predictability and you won't feel like your in a sweatbox!!!

Best - Stan

Good idea, thanks!

make a humidity box for your induced humidity. This kind of standardization really pays off for control in predictability and you won't feel like your in a sweatbox!!!

Best - Stan

Stan,

In your opinion what is best way to construct a humidity box?

Thanks,

Don

Hi Don! A good, simple and cheap box can be made from ½ “ plywood with a hinge top. If you put the humidifier below the box drill/cut-out a 3” diameter hole on the bottom of the box for a 3” PVC pipe from any good hardware store. The humidifier usually has a swivel port for direction of the mist; this swivel can be lifted out exposing a 3” diameter port into the humidifier – so cut the PVC to length for the humidifier/box connection. Above the pipe within the box place a baffle a 2-4 inches above the pipe, this baffle can be glass or anything and roughly 8 X 10” is good, the baffle will disperse the mist evenly throughout the box, without the baffle all you do is get a wet spot in the center of your print.

Probably good to consider the largest size you will ever print before making the box and give yourself an extra 4”on all four sides to allow the mist to work its way to the top without being obstructed by the paper. Place a screen somewhere near the middle of the box for paper and buy a cheap humidity gauge from Radio Shack. An electrical on/off switch somewhere near the lid is good for turning on/off the humidifier from observing the humidity gauge. Opening and closing the lid for observing is a hassle but must be done because as you know you can kill the paper w/ 92+ humidity and run the chance of scorching your negative.

I’m sure there is a cool diy on/off humidity regulator that can control a preset value if anyone knows of such a thing it would be great to post it…

Stan

Hi Don! A good, simple and cheap box can be made from ½ “ plywood with a hinge top. If you put the humidifier below the box drill/cut-out a 3” diameter hole on the bottom of the box for a 3” PVC pipe from any good hardware store. The humidifier usually has a swivel port for direction of the mist; this swivel can be lifted out exposing a 3” diameter port into the humidifier – so cut the PVC to length for the humidifier/box connection. Above the pipe within the box place a baffle a 2-4 inches above the pipe, this baffle can be glass or anything and roughly 8 X 10” is good, the baffle will disperse the mist evenly throughout the box, without the baffle all you do is get a wet spot in the center of your print.

Probably good to consider the largest size you will ever print before making the box and give yourself an extra 4”on all four sides to allow the mist to work its way to the top without being obstructed by the paper. Place a screen somewhere near the middle of the box for paper and buy a cheap humidity gauge from Radio Shack. An electrical on/off switch somewhere near the lid is good for turning on/off the humidifier from observing the humidity gauge. Opening and closing the lid for observing is a hassle but must be done because as you know you can kill the paper w/ 92+ humidity and run the chance of scorching your negative.

I’m sure there is a cool diy on/off humidity regulator that can control a preset value if anyone knows of such a thing it would be great to post it…

Stan

Hi Stan,

Thanks for the information about the humidity chamber. Let me try to break this down into steps to make sure I'm clear about the workflow.

1) Coat paper and let the coated paper rest for a minute.
2) Dry paper with cool air until emulsion and is dry.
3) Place paper in humidity chamber and humidify until RH of the chamber is about 85%.


I do beleive there are RH units with remote sensors so the RH meter could be placed on the exteriror of the box. What would cool is to have a way to have the cool mister turn itself off and sound an alarm when the right humidity is reached.

Say hello to Pam.

Don

Hi Stan,

Yeah, I'd noticed those thin lines - I'm glad you are seeing them too, so it's not an artifact of my diginegs.

Hi guys,
I just went through the process of puzzling out what was causing those lines in some gum test prints I was making; I'm surprised I've never seen any mentions of this artifact before, since so many people reportedly are using this paper for gum.

I don't use it myself for printing, preferring Arches Bright White, but I did buy a few sheets several years ago just to see if I was missing something. I didn't care for its surface qualities, and went on using the Arches. A few weeks ago I decided to size those sheets of Artistico and use it for test prints, just to get it out of the drawer. I couldn't understand why I was getting these visible lines in the test prints that looked like banding in the negative printing onto the gum, when I couldn't discern any banding in the negative even on a light table with a loupe. Finally, when I printed the same negative on my usual Arches paper and got no banding, it became apparent that the paper was the problem. (Strangely, I don't notice these regular horizontal lines when looking at the naked paper, even with a loupe or magnifying glass; they only really become obvious to me in the print).

I'll be incorporating this comparison into my web page on paper for gum, but I'll share it here in the meantime (detail slightly enlarged):

Hi All,

Regarding lines on Fab Art paper: I think that you're looking at the screen drying pattern. I regard that side as the back side and do all my printing on the patternless side - what I've always considered the front.

d

Hi All,

Regarding lines on Fab Art paper: I think that you're looking at the screen drying pattern. I regard that side as the back side and do all my printing on the patternless side - what I've always considered the front.

d
Denise,

I disagree, that's the screen pattern on the surface of the paper. It's very fine but shows up predominately when scanned. In other words that's normal for that paper with a light coat of gum/pigment. When printed with several coats of gum over palladium it more or less disappears.

Don

[quote=Katharine Thayer;4804]Hi guys,
(Strangely, I don't notice these regular horizontal lines when looking at the naked paper, even with a loupe or magnifying glass; they only really become obvious to me in the print).

quote]

Tilt a virgin sheet in strong light and you can see the fine screen pattern. It's there every time.

Don

Denise,

I disagree, that's the screen pattern on the surface of the paper. It's very fine but shows up predominately when scanned. In other words that's normal for that paper with a light coat of gum/pigment. When printed with several coats of gum over palladium it more or less disappears.

Don

Mmm.... not acceptable to me.

I agree with Don as to the direction; I was taught that the front of the paper is the side from which the watermark reads correctly, and that's the side that the screen pattern is on.

By contrary, I always used the back of Arches Aquarelle because I didn't like the regular screen pattern on the front. But I use the front of Arches Bright White because it's the smooth side, and there's not a hint of a screen pattern to it.

Hi Stan,

Thanks for the information about the humidity chamber. Let me try to break this down into steps to make sure I'm clear about the workflow.

1) Coat paper and let the coated paper rest for a minute.
2) Dry paper with cool air until emulsion and is dry.
3) Place paper in humidity chamber and humidify until RH of the chamber is about 85%.

I do beleive there are RH units with remote sensors so the RH meter could be placed on the exteriror of the box. What would cool is to have a way to have the cool mister turn itself off and sound an alarm when the right humidity is reached.
Don

1) yes
2) yes
3) I go for a constant 83% for 15 minutes.

I have a few of the remote RH meters sensors and they all read something different and slow to readjust. Yes - an auto off/on for a preset RH would be great!

Stan

Ok guys, you've got me confused (it's easy enough to do, so don't be too proud :))

I say: "...screen drying pattern." Don says, "Denise, I disagree, that's the screen pattern on the surface of the paper."

What am I missing here? Fabriano Artistico is a mould made paper. That means there is a pattern on one side. That side is considered the 'back side'. I can see it under darkroom light, but then again, I go through a dozen sheets of the stuff a week. Paper manufacturers don't follow any particular rules about watermark placement, so they're not considered a foolproof way to side a paper.

On the other hand, what possible difference does "front" or "back" make to an artist? Use the side that appeals most to you.

d