Author Topic: Digital image workflow help  (Read 1053 times)

zahc

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Digital image workflow help
« on: October 01, 2012, 10:36:11 AM »
I'm a real noob at digital imaging, so please help me out.

I am making photograms by printing real-world objects directly to lithographic film. The resulting photogram can be used as a stencil in manufacturing, and retained as a reference for QC.

I would like to digitize these photograms in such a way that dimensionality is maintained, and I can print copies onto clear sheets. This way, I can send the files overseas, instead of sending physical items. What is an acceptable digital format that will facilitate this kind of life-size printing? PDF? Postscript?

It may be simple to just plop the litho film onto my office's copier/scanner and 'scan as pdf'. Then, if I print the resulting pdf files back to clear film, I assume that the print will be dimensional, to the tolerances of the scanner/copier. Is this a valid assumption? What 'gotchas' might there be? For example, if someone tries to print them onto A4-size clear sheets instead of 8.5x11, I don't want the dimensions to change.

I might wish to do some image processing for contrast, inversion, etc. which might require me to convert the pdf to some more standard image format--I don't know if pdf files can be natively manipulated. In that case, I'm not sure how I can maintain dimensionality such that I can convert back to PDF and maintain scaling. If you were faced with this task, what workflow would you use? Any advice is appreciated.
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Harold Tuttle

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Re: Digital image workflow help
« Reply #1 on: October 01, 2012, 11:03:13 AM »
pdf is a container for content

jpgs, TIFFS and postscript from illustrator or photoshop can be exported into pdf

as long as you stay with adobe acrobat generated content you should be OK

3rd party exports to the pdf standards are sometimes not standard

i would shoot the images to 300dpi TIFF on a scanner including x&y ruled scales on the sides
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zahc

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Re: Digital image workflow help
« Reply #2 on: October 24, 2012, 09:44:31 AM »
Ok so I had an image scanned at 600dpi to TIFF. Now I would like to print the file and see what I get. Obviously I now need a way to print the image to the same size as the original. However, I cannot figure out a way to print an image actual-size. When I try to print the file in Windows 7, I can't directly send the file to the printer; Windows pops up this dumb 'picture printing' wizard, and there is no 'print actual size' option available.

I'm still confused if the TIFF format actually contains data about the real image size.  When I use Imagemagick's "identifiy" utility, it only prints the pixel dimensions (5100x6600) and doesn't seem to find anything about the image dimensions.

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Harold Tuttle

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Re: Digital image workflow help
« Reply #3 on: October 24, 2012, 10:23:11 AM »
Image dimensions are loosely associated to print size
Most imaging software a assume a 72-100 dpi environment, so an 8 megapixel imager creates a 22 inch wide image...

Dots per inch is relative to the reproduction halftone screen of the imaging device

You used to want to reproduce a 150 dpi screen with 1.5 to 2.0 x data to insure the dots were well resolved.

Stochastic imaging engines have changed this repro rule.

600 dpi should resolve rather nicely up to 2x of the original size of the source.

I would import the imaging into a layout program and scale the output to your printers page size there. Photoshop has a sale image to fit to page option.
What you don't want to do is slam 600 dpi data shot at 11x17 onto a 300 dpi laser printer at 8.5x11. The printer will churn for a while and print the same image that you could of had in 1/4 the time, if you scaled the data properly.

What is the spec on your printer? Is it a postscript laser printer?

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He strikes from below like a viper or on high like a penny dropped from the tallest building around!
He only has one purpose--Do bad things to good people! Mit science! What good is science if no one gets hurt?!"

zahc

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Re: Digital image workflow help
« Reply #4 on: October 24, 2012, 10:45:05 AM »
The printer is an unknown. This is what I'm trying to get at. Why do I need to know what printer I am going to use, in order to know how the image is going to print out? Isn't there some image format that will print out the same size on any printer?

I'm trying to reproduce a physical original. I want to scan it directly from the real-world original, save it in some format that saves the image dimensions so that I can print it out life-size. Is this some difficult, unsolvable concept in digital imaging? Isn't there a file format that simply contains the image dimensions in the header information, so that it can later be printed out to that dimension?

I'm starting to think that maybe I should really be using CAD files. Maybe I should import my image into a CAD program, set the dimensions in the CAD file? Then how do I print THAT out?
Maybe a rare occurence, but then you only have to get murdered once to ruin your whole day.
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