Is eps the right format for photos with transparency?

Question

I have just started with a company who make a 72pp catalogue of products. There are hundreds of linked eps files used for the product photographs (electrical trade products so typically white and awkwardly-shaped). The catalogue is put together in InDesign CC and sent to the printer's as a pdf.

As I understand it, eps files are used because they offer transparency, which is necessary when dealing with many images layered over blocks of colour etc. on the page, and I obviously don't want to (re)make clipping paths for thousands of images.

My first instinct is to try to move away from eps to pdf, for the sake of file size if nothing else, there are linked eps images ranging from 92kb to 185mb(!) in size for pictures never larger than just under A4 and generally only about 20mm wide.

I've googled around for a clear answer but anything about eps focuses on vector graphics, and there's no obvious finished image file answer for photos with a transparent background.

Am I right about moving to pdfs for such small images and if so, is it worth converting nearly 10k images?

Answer 1

There are several issues here.

1. The "damage" is aparently already done.

2. There is no real damage. EPS is an old format but widley supported. Yes, there are better options to save transparent bitmaps.

   • For RGB files PNG and PSD.

   • For CMYK TIF and PSD.

Regarding the compression there are several ones on each format. On TIF just do not use JPG compression.

obviously don't want to (re)make clipping paths

3. You nailed here! There is a chance the images are on EPS because the transparency is not on the bitmap itself (as alpha channel or mask) but as a clip path. In this case the EPS solution is ok.

4. The real problem of the EPS and PDF format is that you could mess up the real resolution of the bitmap inside.

For example a file could have a bitmap at 400 ppi, but a declared resolution of the document of 300. When a raster program want to open it, it could just use the 300 instead of the real resolution of the file at 400.

5. In my opinion there is no real need to change format, the storage is so cheap this days that I would not bother in converting then all (your time is more precious). Unless you need to "extract" some recurrent images that you will be using on several places and you have a real issue of compatibility.

In that case open the EPS in a vector based program like Ilustrator or Corel Draw, and extract the image inside. Export it as it native resolution, edit it and save it or try copy pasete.

6. If the image do have the transparency as a clip path, it is probably a better option to leave them as EPS, because some programs understand that a EPS is an "importable" file format. PDF is normally considered a final output format.

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Offtopic.

ranging from 92kb to 185mb(!)

Be carefull of the quality of the images... I would be using the expression mark on the first case. 92kb! That image is probably usless.

I can live with a 185 mb file, if it is worth it. But again check what is really inside that file.

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Aditional options for batch converting files:

Prepare a batch action in ilustrator: https://helpx.adobe.com/creative-suite/kb/convert-multiple-ai-files-eps.html

Or try using ghostscript, a free aplication but using a comand line: https://www.google.com.mx/search?q=batch+eps+to+pdf+ghostscript

Answer 2

Adobe Creative Suite, since it's beginnings, was optimized to integrate InD, AI and PS.

When using InDesign, the best way to place images with a transparent background is to simply save your PSD file as a PSD making sure the background is deleted and you see the transparency grid. That's it, no need for a clipping path, or to save as TIFF (it will not work with TIFF), EPS or PDF.

You can now place your PSDs directly in your InDesign catalog and layer away.

Answer 3

EPS files are typically used for vector images as far as I know. I wouldn't choose EPS for dealing with photo transparencies though. Try using TIFF or PSD instead. It would be so much easier on the program.

Answer 4

If you want to get rid from eps file. Then you can simple merge that eps file. After this there is no need to keep your linked attach file.

Or you can convert your eps files to tiff format.

Answer 5

I'm now wondering if for the sake of file size and cross-team usability (i.e. staff without PS), I'd be better off using jpg with photoshop paths saved in the metadata.

I use InDesign at work every day and do exactly this for the same reasons. And, there are other benefits, too. With no noticeable loss of quality, an eps file can be saved with a clipping path as a jpg, creating a much smaller file size. This not only saves disk space (which is usually more or less inconsequential in most cases), but it also makes far smaller finished document sizes, which, in turn, takes less time to FTP to your print shop, and far less time to rip to a printer. This helps the workflow from the top down; everyone benefits.

Also, an action can easily be made to convert eps files to jpgs with clipping paths intact for entire folders of files at one time. If you continue to use some of the same images repeatedly, it may well be worth your time to batch convert to jpg the ones you need as necessary. And if there ever might be a future case where the eps file might be necessary or helpful to have, if disk space allows, you can always convert to jpg and keep the original eps in an archive.