Hi all,
Would like to know the uniformity of the dot percentage ( say 50%) over the full exposure area (of a Pano plate of size like 568mm x 695mm) of different makes of CTP, especially Agfa Polaris XTV and Agfa Advantage 3850 DL. Is there a specification from the manufacturers for this?
Is this screen dependant? Is it resolution dependant?
If you're trying to test the platesetter to see if it is able to image consistently across the plate then here are a few suggestions:
1- make a small test patch say 1" x 1" it should contain 8 patches: 1%,2%,3%,50%,97%,98%,99%,100%. Step and repeat this oatch across the entire surface of the plate.
2- put a strip of scotch tape/cellotape diagonally on the back of the plate from one corner to the other. This is to simulate the impact of a dust particle or some other contaminate when the plate is exposed.
3- expose two plates - but only pricess one.
4- take the exposed unprocessed plate and put it in a protective envelope.
5- one or two days later take the second unprocessed plate and image it a second time - then process that plate. This is to test the device's ability to remake a plate that is consistent with previously imaged plates despite changes in the environment. I.e. If one plate gets damaged will you have to image just one or all four?
Now examine the two plates. Note the dots on the single exposure plates. Are all %s imaged consistently? Are all dot %s imaged or do some fail to image. Look at the dots left and right side, corners and center. If you can see a line caused by the scotch tape then the imager may be subject to hotspots. If certain dot %s are not imaged then that shows you the limitation of the imager.
Look at the plates that was exposed twice. Can you see if dots are doubled? If so, where does this occur. That will help you see if the imager consistent day to day and if the dot doubling is directional, where it occurs and what may be the cause.
Gordo