I have a file in Illustrator that I'm trying to place in InDesign. The final size in InDesign needs to be 585 x 295 pixels. No matter what I do, it will not place it at that size, hi res, cmyk. The original Illustrator file is cmyk, and I exported it so that the dimensions are correct. But once placed in InDesign, while it says in the link details the file is correct, it looks MUCH smaller in the file. I've tried placing directly from Illustrator, changing resolution in Photoshop, but nothing works. Could someone please help me figure this out? Thank you!
This may simply be a problem with inDesign honoring (or alternatively, assuming) the ppi of the artwork being placed.
InDesign supports "random ppi imagery" in that you can have art that has an effective ppi of 72, 300, and 1200 all on the same page. It does make assumptions, though, when you enter a pixel value in the (new) document setup: it assumes 72ppi, and calculates an inch-based measurement for the document based on that. A 72px x 72px would be a 1 inch square.
So if I make 2 new documents and in the page size fields I type: for "A" 1.95 x 0.8633 inches and for "B" 585px x 295px then B will be the same aspect ratio as A, but it will be 8.125 x 3.5972 inches.
I chose 1.95 x 0.8633 because that is the desired px dimensions each divided by 300ppi (rounded slightly).
A tiff (or any art type) that is 585 x 295 px will have two possible behaviors when you simply "place it" by clicking the page without dragging it to size in inDesign. If you have set a dpi flag in the file, then the flag will be honored, and the inch-based sizing will be calculated when you drop it unsized. If there is no ppi flag, then it will use 72ppi (and hence it may appear too large).
I presume you set the document size using pixels values, since in the particular case where you create the inDesign document using pixel sizing (document B), but your art is 300ppi, then the art will appear about 1/4 size (300/72 = a factor of 4.16666). If you then simply enlarge it by 416.6666%, it will be sized properly. Then if you look at the link details, you will see actual ppi of 300, effective ppi of 72.
If you were to then export this as PNG, you'd want to export at 72ppi.\
When dropping that same 300ppi tif file into document A, it would fill the page perfectly. If you would export this to PNG use 300ppi.
Always remember: ppi means pixels per inch, it is meaningless without both inches and pixels. Without resampling, ppi is a see-saw: when one value goes up, the other goes down.