Film calibration problem

[MICHAEL GREENWALDT]

On my film test run my 50 % is reading at 63% , however my density is right where it should be and my 100% tint is fine.Any ideas how to get my 50% calibrated right?

 

[Al Ferrari]

It would be a good idea to let us know what density you are actually getting.

 

[Lukas Engqvist]

Is the laser clean? Are we talking NEG or POS? Is the raster sharp?
If a negative film is right density at 100% also check the 0% to see that the laser is strong enough/not too strong. Then you would normally in your process add a linearisation curve.

 

[DonBlock]

Depending on the Imagesetter you have, it is normal to have that amount of gain on the film UNCALIBRATED. If your density is above 4.0, then it is ok and as Lukas said, you have to create a calibration curve to make the film linear. This is done in your RIP and the process is dependent on which RIP you have.

 

[Prepress_Parasite]

What kind of film and imagesetter are you using? If I can recall the way we used to have our Kodak film setup was to set the exposure so that the uncalibrated 50 percent dot was 54 percent. Your solid density has alot of latitude and if you are using good film you should be able to drop your exposure back and then setup a calibration curve to help make things linear.

 

[GinSu]

Perhaps I'm old school, but don't forget DMin. Plate-able film has a DMax of 3.6 or better and a DMin of .03 or less. If neither of these values measure right, dump and rebatch the chemistry in your processor before doing anything else.

 

[DonBlock]

DMin is only an issue with the Fixer, not the developer. It should be below .03 and if not you could get an unseen image, background on your plate that may pick up ink.

Without knowing which Imagesetter you are using, it is going to be hard to give much more advice than what has already been posted.

Make sure the DMax is over 4.0, and then you need to concern yourself with the dots.

 

[Naeemi]

Hi Everyone

 

[sayky]

It should adjust the curve of calibration in imagesetter...