Blinding problem

[jzaloom]

Untreated water is one of the causes for plate blinding. By untreated I mean no Deionization or Reverse osmois treatment.The calcium in the water needs to be removed because it will form insoluble salts when emulsified with the ink. These salts deposit on the image and render the image non ink receptive. Also calcium in the paper that is not chelated will form insoluble salts( the job of a good fountain solution).
Adding chemicals to treat the water is a hit or miss in controlling calcium. Depending on where the source of the water comes from will determine the amount of calcium in it. I highly recommend that an in-house water treatment system be used along with a good fountain solution.

[Hessel]

Well the problem is we are not the only company with these problems. There are some in the Netherlands, Belgium, Germany, Spain. And some have a 10.000 liter tank , some use normal water. We also tested with this.
Today i already saw the lines in the plate before printing. Very strange.

Last week we tested with 1 year old chemicals Agfa had in stock and the result was mindblowing. The solids on the plate were black as it should be and not gray. The print was much better, less waste starting up and a visible much sharper print. So Agfa's comment nothing has changed since 3 years in the chemicals can also be flushed down the drain.
Tonight we will do a 170K production on Fuji plates. If there is no blinding tonight we know the cause of our problem.

[Hessel]

Here's an image of the difference

[Lukas Engqvist]

Be iinterested to know if it wsa the old chemicals or the fact that the chemistry was remixed. Using a fresh batch of new chemistry would have the same effect? If so then how is your chemistry re-plenished?

[Hessel]

The left plate (best result) was with the old chemistry. Agfa keeps 10 x 20 liter cans on stock of each batch. So thats why they could send us this. The current chemistry is the plate on the right.

If i drain all chemistry and renew it with my current chemistry it still does not give the same result as the old chemistry.

[Lukas Engqvist]

Probably somthing that kills the environment in the old stuff ;P (chemistry that is replaced by "green" "equivalents")

[Green Printer]

We had bad chemistry a few years ago. Its was traced to an Agfa contract chemical manufacturer. Of course there wasn't chemistry problems according to Agfa. After the problem was fixed then there was admittance of a chemical problem. Keep on it.

[Green Printer]

Also there are chemicals in the chemistry that make the plates INK RECEPTIVE.

[Hessel]

New developement:

Agfa and Fuji polymer plates also blinded. We will test Kodac Thermal plates soon but things are pointing towards the Flint ink more and more in my opinion.

[Hessel]

We narrowed the options to the plate thickness. Last 5 weeks the problem was gone. When i measured the plate thickness it was 0.28mm. This week the blinding appeard again on 027mm thick plates. Goss tells me the minumum has to be 0.28mm. The fuli plates we tested were also 0.27mm. So well wait and see.