Most journals require high-resolution images for publication. Adobe Illustrator is an excellent option for figure creation that allows this, but many people are more comfortable creating figures in PowerPoint. Despite the ability to save TIFFs from PowerPoint 2008 with a selected resolution up to 1200 dpi, the resulting files do not actually have this resolution. Even PowerPoint 2011 has a maximum resolution of 300 dpi. This is my workaround for this problem on Mac OSX systems.
- Save the PowerPoint file containing figure(s) as a PDF from PowerPoint. Select “Print.” Then click the “PDF” button and select “Save as PDF.”
- Drag the PDF file to Photoshop or select File->Open from within Photoshop.
- The Import PDF dialog will appear. You will need to import each slide/page separately. Select the first page you wish to import, then select the resolution you need, and the color mode (RGB or CMYK, depending on the journal).
- Your slide will open as a Photoshop image. Crop as necessary using the crop tool.
- Resize as necessary using the Image->Image Size.
- Select Layer->Flatten image.
- Select File->Save as, and choose TIFF as the format.
- In the TIFF options dialog that then appears, choose LZW compression. This is a lossless compression that offers much smaller file sizes than uncompressed, useful for uploading to journal servers.
- Leave all other options unchanged, click OK.
- If unsure of the success of this process, open your TIFF in Preview, hit command-I, and check the resolution and color mode.