Question about plate curves

[gordo]

I need to confirm my understanding.

If one is supplying halftone screened bitmaps for output to plate - say from a remote prepress location - then any plate curves that the printer is using for their normal plate imaging will have no effect.
Put another way.
If the printshop is using a curve to linearize their plates in their normal workflow, if I send a prescreened one bit tiff for output to plate that linearizing curve is not applied.

 

[[email protected]]

I believe you are correct Gordo. You could however, apply the same curve adjustments in the remote workflow to produce tiffs with the correct tone values. Sometimes this is press-specific so some communication and planning would be necessary.
Also I suppose, if unadjusted tiffs were created, they may be able to be modified in DotShop to yield the correct tone values at the destination site. I am not aware of an automated system to adjust bitmap tiffs for tone value but maybe someone else is...

-dan

 

[cementary]

If one is supplying halftone screened bitmaps for output to plate - say from a remote prepress location - then any plate curves that the printer is using for their normal plate imaging will have no effect.

This is 100% true, but have to add that it affect any bitmap — doesn't matter if it is raster data or anything else (0,1)

If the printshop is using a curve to linearize their plates in their normal workflow, if I send a prescreened one bit tiff for output to plate then linearizing curve is not applied.

RIP knows how to alter 8-bitt data before converting to 1bit raster. I personally don't know any RIP that can alter 1bit data directly. But if one will use, say, descreen option before output — then it is possible, but anyway, it involves some steps between "recieve file —> output to plate"

 

[SZmetana]

Normal calibration on output won't touch 1-bit data, bit it is possible to run a curve on one-bit data. For instance, if you have the "Copydot Calibration" option in Prinergy, you can run a calibration curve on one-bit TIFFs. The algorithm does edge pixel dilation/expansion, and halftone dots maintain a reasonable shape. You can even run a curve on Staccato, but Staccato will lose its printability, if it's anything more than a slight correction.

 

[Magnus59]

That is correct, the plate curve must be applied to the Tiff output

 

[gordo]

Thanks all for the responses.