1 bit Tiff problem

[printPlant]

My customer send me 1 bit tiff on 2400dpi but my CtP recommendation only 1500dpi. I don't know what dot shape and lpi they used. i need to convert 1 bit tiff on 1500 dpi. How it possible i convert the 1 bit tiff without change dot shape, lpi.

[gordo]

My customer send me 1 bit tiff on 2400dpi but my CtP recommendation only 1500dpi. I don't know what dot shape and lpi they used. i need to convert 1 bit tiff on 1500 dpi. How it possible i convert the 1 bit tiff without change dot shape, lpi.

If they were able to create a 2400 dpi tiff - have you asked them if they could send you a 1500 dpi tiff instead?

The alternative - and it's a stretch - is to find someone who can descreen the 1 bit tiff using software that came with copydot scanners. Then you would rescreen the file in your RIP. You should be able to tell the dot shape by looking and the tiif file.

best, gordo

[printPlant]

thanks gordo
Do i RIP again 1-bit tiff on 1500dpi. Will the Dot shape and lpi be change in 1-bit tiff or this will decrease only resolution.
What you think....

[ssutton503]

I have never tried this and have no idea if it will work or if it would be a good thing to do but... Could you downsample the 2400 dpi tiff to 1500 in Photoshop?

[gordo]

I have never tried this and have no idea if it will work or if it would be a good thing to do but... Could you downsample the 2400 dpi tiff to 1500 in Photoshop?

You could but the rsults will be garbage.

Best, gordo

[gordo]

thanks gordo
Do i RIP again 1-bit tiff on 1500dpi. Will the Dot shape and lpi be change in 1-bit tiff or this will decrease only resolution.
What you think....

Dot shape will not be affected by dpi. Lpi, within reason, will not be affected by dpi.
If you are the printer then it is your job to say what dpi/lpi/dot shape you require for supplied 1 bit tiffs. At the very least you need to discuss this with whoever is supplying you with the 1 bit tiffs. It is better to get the art you need supplied correctly than to try and "fix" it.

Best, gordo

[Colorblind]

If they were able to create a 2400 dpi tiff - have you asked them if they could send you a 1500 dpi tiff instead?

The alternative - and it's a stretch - is to find someone who can descreen the 1 bit tiff using software that came with copydot scanners. Then you would rescreen the file in your RIP. You should be able to tell the dot shape by looking and the tiif file.

best, gordo

I used to work on a Esko copydot scanner and the editing software (name was Perfection I think) that came with it could change resolution of 1 bit tiff files without descreening. We used it to change (old workflow) backed-up 2540 dpi 1 bit files to be able to output to our newest 2400 dpi device.

[printPlant]

Dot shape will not be affected by dpi. Lpi, within reason, will not be affected by dpi.
If you are the printer then it is your job to say what dpi/lpi/dot shape you require for supplied 1 bit tiffs. At the very least you need to discuss this with whoever is supplying you with the 1 bit tiffs. It is better to get the art you need supplied correctly than to try and "fix" it.

Best, gordo

sorry one more question:
If i resample 1-bit tiff in Kodak Tiff Assembler Pro then what happens?

[printPlant]

You could but the rsults will be garbage.

Best, gordo

What change in 1-bit tiff after downsample in photoshop?

[gordo]

What change in 1-bit tiff after downsample in photoshop?

If you resample in PhotoShop you will very likely get artifacts like moiré which you might not see in the 1 bit tiff if you look at it on your display but will be visible in the printing. It would be easier if you were going from 2400 dpi to 1200 dpi because 1200 is an even divisor of 2400 (2400/1200 = 2) but 1500 is not (2400/1500 = 1.6). Because it's not an even divisor there will be extra and/or missing pixels. Those will create the moiré/artifacts.
It is not an easy thing to resample 1 bit halftone screens which is why you need specialty software.

best, gordo