Ryobi 512 Colour in printing

[starprintingltd]

Hi,

We currently run a Ryobi 512 using posi plates. Exposures are brilliant and things are going good when doing 2 colour work.

The problem is when running four colour work. I wanted to know how do I check how much ink I need, i.e how much cyan, to put on etc etc.

I don't have a densitometer but there must a way to check how much to put ink on.

At the moment I just guess and put ink sweeps between 5-6. can anyone help?

Thanks

[RGPW17100]

For consistency you will want a densitometer. For now just use a pms book to match the color. You might want to put a couple of screens in your color bars so you know you are keeping the screens open.

[starprintingltd]

I have a pms book but please help as I am an amateur at colour matching etc...

If I have a pms book which I do have , am I right to believe I need to match the yellow colour bar to the one in the pms book.

And I don't know what screens mean can you go through a process with me. I will really appreciate it alot

Please let me know and thanks alot for the reply

[RGPW17100]

On the tail of the sheet you should have color bars. CMYK. they should be at least 1/4 inch square. Within these color bars you can add say a 40 percent screen of each of the CMYK colors. When running find the coated or uncoated swatch in your PMS book for Cyan, Magenta, Process yellow and black and try to match those colors. If you run the colors too hot the screens in the color bars will begin to plug. A densitometer is the best way to go and using a PMS book will not give you consistant results because the color drift on the sheet would be detected on the densitometer much faster then your eye.

[PatQcCa]

One thing is shure...

If you don't have a densitometer, you won't be able to do a good process job.

Your wright, for spot color a PMS chart is ok.

Every slight differences between 1 cyan square of the color bar between the next sheet, combine with an other slight difference between the black square of the color bar from a page to an other...multiplying whit 4 colors or 2 pass in your case will give you a very bad result! Unconsistant images or colors...and maybe plug screen.

Very Basics explanations, but that will give you a good idea of the mess you should have!

(bad english, sorry)

Pat