Plate developing

[Rowenf]

Hi all
How do I burn (on my own light box) and develop perfect printing plates (Litho printing) without leaving any background. Is there perhaps a website that I can visit where I can learn more about developing printing plates?

 

[Tommy B]

plate developing

plate developing

Are you using a processor or hand developing? Single or double sided plate? What brand plate? What kind of film are you making the plate from, camera or imagesetting?Let me know and I will try to help

 

[Rowenf]

Hi Tommy.Thanks for the reply. I am using hand developing. I print my image from a lazer printer onto Kimolec. I use Novasharp Bright White Matte (Pearl) Laser Printer film. My plates are 492 x 330 Agfa. I have my own lightbox with a 300 Watt bulb in it. I currently burn my plate for 11 minutes and leave it in the positive developer for aproximately 6 minutes. I do however still get background shadow on the plates. If I burn the plates longer the image washes off. Would you be so kind as to explain to me the developing process so that I can have a better understanding of the process? I have worked for years in the paper industry. My business cam edown with a terrible crash leaving me with nothing. A friend gave me an AB Dick 9840 printer and the lightbox. I operate the printer farely well now and have done some jobs and I can get even more deals, but I have to sort the developing out.
Many thanks for your reply again.

 

[Tommy B]

Kimotec

Kimotec

We feel that your density maybe too low and you are having to expose too long. Try this product from Kimotec


From their web site:

The optical density of KIMOLEC PF-90S laser film depends on the laser printer's toner technology. If a higher density is required, the simplest and cheapest method for occasional after treatment is Kimoto's KIMODENS PF-DENS SPRAY. It contains a special agent that refines and homogenises the grain size of the toner. This increases the density value up to 3.5
Spray evenly on the exposed side of the Kimolec PF-90S film from a distance of 30-40cm. The film is ready to be exposed after few minutes drying time.

This may help in buring the plate

What laser printer are you using?

Tom

 

[Rowenf]

Thanks Tom

Don't laugh: A samsung ML-2010. Best that I could afford at the time.

Rowen

 

[VladCanada]

And give us more info about plates you use, please (AGFA, positive, and what's the name).
6 minutes of developing - toooooooooooo much!

 

[Jim-CompuDoc]

6 minutes of developing - toooooooooooo much!

The plates should develop almost instantly.
Use a scrungy pad (hard backed with a handle) soaked in developer to lightly scrub them, the coating should come right off.

 

[danremaley]

Hi all
How do I burn (on my own light box) and develop perfect printing plates (Litho printing) without leaving any background. Is there perhaps a website that I can visit where I can learn more about developing printing plates?

I'll assume that your using POSITIVE films to burn your plates. The correct exposure is 6 to 8 microns on a UGRA scale. You may need to make a (protection) "mask" of the image area and expose the plate a second time to clear out the background.
Negative plates should develop with no background left behind.
Your "light box" should have a vacuum pump on it.
"Google me" for more info or email me. . .hope this helps.
Dan

 

[Rowenf]

Hi guys

Taking all the advise into account, I experimented some more and discovered that my exposure time might be to short. I lenthened it slightly with another minute and got better results. I checke also on the developing time and halved that. I think that the secret lies between the exposure lenght and developing time. I also used Tom's advise and baught a Kimo enhancer. This could alo have attributed to the better results.
I will experiment some and leave the results on here. Maybe there are other guys who can also benefit from it.
Many thanks.
Rowen

 

[162Lehi09]

Plate Exposure:

Plate Exposure:

Hi, there. I still can remember exposing plates with film negatives. If you have negative grayscale, it can help. If not try this elementary approach: cover your metal plate with a solid black film and make "steps" at 15 seconds interval. Make the same process but this time do it with a 15% screen at the same 15 seconds intervals and "steps".

After developing, inspect with a loupe. Pick a range that you think is reproducible by your press. Make a one good exposure from out of the range that you pick. Hopefully, it will be right (in terms of dots) and your background "tinting" is eliminated. I suppose you are using negative "subtrative" plates. My 5 cents.