by
lmh » Mon Oct 05, 2009 3:58 pm
TIFFs are bitmaps, and Powerpoint is really bad at handling bitmaps because it's a vector graphics (graphic object) orientated system. It remembers that something is a line starting Here and ending There, rather than a row of pixels on a background of pixels.
Once you've pixelated something that was originally a set of lines, it becomes very hard to change. The process of converting a line graphic into pixels also forces you (or someone, somewhere) to choose the resolution, and if it's badly chosen, you are doomed to blocky pictures.
I've found that the best way to deal with chromatograms for publication is to export the raw data to any genuine graph plotting program as csv data (i.e. genuine numbers) and replot. This way the plotting program can stay in line-graphics-world without pixelating, and add all my annotations and get the axis labelling right. Once I'm happy, any decent graph plotting program will provide an ability to export in any number of different bitmap formats (tiff is sure to be there), and most importantly, at any resolution I choose.
Personally I use SigmaPlot, but there are many others.
Good luck!