Creating a High Resolution Bitmap file for Stamping/Emboss Plates

[amybethm222]

I know everyone has different methods of working, but Im curious as to how you are preparing bitmap files. Let me preface this by saying by all means vector is always better, but not always an option. I work at  publisher and often we have 300dpi,  raster titles ( for example ) that need to be a 1200 dpi (ppi) 50% threshold bitmap images, saved as a psd. Just looking to get the best results. I know its always based on what you begin with. This is my method.

1. Convert art to Gracol Black ink 2006
2. Apply a curve so there are no tints and all art is 100%k
3. Increase image size to 1200 using bicubic smooth gradient ( this sort of does the same thing as a Gaussian blur)
4. Flatten
5. Create Curves adjustment to clean up edges
6. if needed create smart object to apply Gaussian blur (smart filters) if edges are still jagged
7. Convert to Bitmap Mode, save as psd.

thoughts?

Looking for a baseline method. I know every file needs the human eye to look at it.

Photoshop CC2018

[JJMack]

If you do not have vectors graphics  resizing will be done via interpolation if you are keeping the print size the same.  Going from 300DPI to 1200DPI is a 1600% increase in the number of Pixels 16x.  Try all the different Interpolation methods on your content see if one works better that the rest. 16x  is quite a large increase in size.   Why do you need 1200DPI?

[amybethm222]

Required by our print / finishing vendors. Just looking for optimal results.

[Mike_Gondek]

I never have a need for bitmap files and happlly avoid them. Would need to work at 2540 or 3386 dpi to match vector quality,  files get slow or get errors about too many pixels adn in bitmap mode some important Photoshop tools do nto work..

For flexo or roto gravure printing on plastics we have a very high minimum dot, so will take a gradient or drop shadow and make that bitmap, but only 300 dpi since we do not need a hard edge, just to make a fake stipple dot gradient with spaces in between solid 100 ink rather than screening the ink.

Initially back around 1985 we would get a logo on RC paper or film and scan that at 2400 (as that the setting the scanner had to closest match the the 2540 dpi available at the time). But noone works that way anymore as everyone has vector logos, or on rare occasion we will hand trace that to vector or use image trace.  RIPs are much more powerful nowadays so you do not get crashes, as when for example the L100 was the best expose scanner out there. Bitmap though can cause very slow printing, so that is why we avoid the bitmap format as would cost us more time and less profitable in long run.

[amybethm222]

The situation that Im in, although we always use Vector when ever possible, we need to supply PDF with bitmap images for stamping/ and embossing plates. Can not avoid it unfortunately.

[Mike_Gondek]

I see thanks for explaining. Am familiar with dry offset, litho, flexo, roto, but not others such as letterpress. We had a Digicon 3000 which would do hot/cold foil stamps and emboss, but we sent over vector files for that, but do not know they converted or what that finishing press was considered.

Only advice I can offer is to say using actions should be very useful for you Items  you need to visually tweak (eg: Curves adjustment to clean up edges) you could click the turn dialog on /off.

[Derek Cross]

Is the artwork for making metal plates in zinc, magnesium, copper etc, for letterpress foil blocking?

[amybethm222]

That I cannot answer specifically but the requirement for all non vector artwork for effects plates is bitmaps. Looking for the best technique .

[JJMack]

What kind of artwork has such file detail 1/1200" x 1/1200" are they using a lazarbeam to create such fine art?  Scan it at a higher resolution.

[amybethm222]

OMG really thanks anyway

[Derek Cross]

That's why I was asking about the blocking – the process is (generally) quite crude so you don't need very high resolution artwork for creating the blocks.

[JJMack]

Ask your vender what they actually need.  It is hard to believe they need 1200dpi resolution  4x what the human eye can resolve down to.  One probably need higher resolution  for making computer chips.  What is your vender producing for you?