Re: What is a correct formula for gelatin+glutaraldehyde paper sizing

John Brewer

Hey Don

What’s an RD90 rod? Google isn’t helping me!


On 2 Apr 2021, at 6:14 pm, Don Nelson <ac7zg@...> wrote:

And you might want to mix smaller amounts as it starts to immediately crosslink in solution
I coat 2  12x15 sheets at a time with just 100ml size plus 0.8 gm glut, using a coating rod to spread. A hot rod with eliminate bubbles in the sizing
( rod is a RD90)

On Apr 2, 2021, at 10:10 AM, Don Nelson <ac7zg@...> wrote:

You can use up to 0.9 ml 3% glut solution per 100ml of gelatin sizing (I use 5% gelatin)
More than that and you will start forming polyglut. Polyglut will give a yellow stain in the size and cannot be removed.
Very little glut can actually be used. Two active bonding sites on the glut molecule means a lot of crosslinking activity with gelatin
Don Nelson 

On Apr 2, 2021, at 8:22 AM, job.westerduin@... wrote:

Hi, i have experimented with gum printing (trail and error,, and i will to start serious first gum printing with a cyanotype as starting layer base this weekend or later.

I have a pot glutaraldehyde from Rollei Black Magic emulsion set, that was left over from my previous silver photopaper enlarging hobby
How many glut and gelatin per 1 liter water.

Greeting Job from The Netherlands. 

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