I'm about to prepare a composite image for print and I could use some advice on a proper DPI workflow. The final image size to be printed is 20" x 30" at 400dpi, Lambda C print.
The image I am making is essentially a collage of video stills...these stills exist as TGA 1440x810. These default to 72 dpi when exported from AE.
If I bring these targas into the 20x30 400dpi photoshop document, they are far too small for my composting purposes.
Therefore, should I composite in photoshop with the 20"x30" document set at 72 dpi, and then scale up to 400dpi when I'm finished? Or should I make the targas 400dpi in phoroshop first and then drop them into the larger document? (seems like no final difference, except that I'm then working with larger files)
Also, I noticed that photoshop doesn't explicitly have a "dpi" setting, rather "ppi." Can I take a 72ppi document in photoshop and save it as 400dpi without expanding my resolution?