|
Everyone has brought up good info here. You are too light for sheetfed and way to light for web. Make sure the press in in good operating conditions before proceeding or you will be doing this again later when it is. No real old warn blankets, right packing, etc. Make sure your are properly exposing the plate. You do not have to linearize the plate if you are going to add a curve. what counts is the dot gain on paper. However, if the plate you are using in not too linear, you may want linearize it. Get a QC strip from the plate manufacture, it should provide a test scale with and with out curve. This way, without curve, you can check the 50 to be a 50% as a QC step. If you were content with previous printing, then Lammy is right, follow his test and make curves to match. If not, then for sheetfed, on a good coated stock, you will typically have 18 to 20% gain so a 50 will be 68 to 70%. Make sure when you run the test the pressman runs to standard house densities and the sheets are even across. You may want to read several sheets and average the dots. Once you have the right weight, you can tweak the curve for gray balance if need be.
What is your standard screen ruling? With CtP, you can step it up a bit and provide higher quality ....while your at it.
Out of curiosity, what CtP do you have and what plates are you using?
Regards,
Mark
|
