Poor PNG Image Quality Printing from Excel to PDF
Question Posted on 5/13/10 to various support entities.
When printing an Excel file that contains PNG images (or printing from other office applications like Word) to PDF, the image quality in PDF is poor, as if there is no anti-alias. When I print the same Excel file to an inkjet printer the image quality is good. If I use a jpg image, the quality in PDF is much better, but the file size is also much larger. I've spent some time trying various settings, with no success. I need to produce some work product in Excel, but distribute it to customers in PDF, but in doing so my image quality suffers, particularly when using PNG images. Does anyone know of a way to preserve image quality when printing directly from Excel to PDF? I have Office 2007 and Acrobat 2009 running on Windows Vista
Follow up Posted 5/14/10
Thank you everyone for your input. I did more methodical extermination trying files with and without transparency, and with and without a slight border between the edge of the graphic image and the file edge. I also tried printing to PDF from Excel, Word, Photoshop, and Illustrator. Following is a summary of my perceived results:
The results are much better when not using transparency, which is optional with PNG, but necessary for some objectives. Using a small border didn't seem to help. Increasing the resolution above 150 DPI doesn't help much, nor does setting the option for high quality or press quality print. I did get smaller file sizes using high quality print, but that is likely because the default HQ settings only support backward compatibility to 7.0 whereas standard supports compatibility back to 6.0. Resulting file size seems more related to the backward compatibility setting than the image resolution (for the simple artwork I was testing with).
The best results were achieved by getting the vector graphics into PDF by: creating the non-graphic work product in Excel (or other MS Office application), then print to PDF, open the PDF with Adobe Illustrator and paste the graphic images, then reprint to PDF from AI (printing to PDF will result in smaller file sizes than saving to PDF), but the process is clunky and slows down the workflow. It will get the vector graphics into a PDF file, but there is a time cost. If transparency is required, then the clunky workaround is likely the best option, but if you don't need the transparency or scalable graphics, then using a non-transparent PNG file and saving to a PDF with the High Quality Print setting (in print properties) is a reasonable option that will result in faster workflow productivity.
Printing from PDF from Photoshop yielded better results than printing to PDF from the Microsoft Office Applications, but it still wasn't as good as printing a vector image from AI. Tiff files were too large and didn't support transparency.
Follow up question 5/14/10
Will the Microsoft Office applications accept any vector graphic file formats for image insertion, and if so, can you convert an Adobe Illustrator file to a vector format that the Microsoft Applications will accept? I tried EPS, but it didn't display well in Excel (EPS is listed as a vector format, but it but the images are stored as tiff so...?). Adobe is good at producing graphic content, but some things are handled better by a spreadsheet application or word processor.
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