Photoshop

Image file resolution

Image resolution is measured in units of dpi or ppi, and is expressed in ppi in Photoshop.
The higher the number, the higher the resolution. Since screens are viewed from a distance, unlike paper prints, 72 to 150 dpi is fine.
A common case is when an image is enlarged in Illustrator and used at a resolution of 50 dpi or less.
Please make sure the actual size is between 72 and 150 dpi.
"Image" menu → "Image resolution"
Please check that the resolution is appropriate for the actual print size.

Recommended save format

We recommend that you save any Photoshop images you use in EPS format.
Although it is a highly stable image format, you cannot save it in EPS format unless you flatten the image. Please flatten the layers of the image you submit.
You can also save in PSD format, but if the image contains transparent areas and is smaller than the Illustrator document, white lines may appear around the outline of the image, so make sure to place it the same size as the document.

Save options: Encoding: JPEG - highest quality (low compression)
JPEG - Highest quality (low compression rate) is recommended as it saves images without degrading their quality.
Binary/ASCII allows you to store images without compromising quality, but takes up a lot of space.
Other JPEG compression methods result in lower image quality.
Please uncheck all the check boxes.
The TIFF format is also an image format commonly used in DTP, and can save layers as well, but please make sure to flatten the images in the submitted data.
Please do not use Photoshop DCS format, as the file extension will be "eps" and it will be indistinguishable from EPS format.
The JPEG format, which is commonly used for saving data, is not suitable for printing data because the image becomes degraded each time it is saved due to compression.
GIF/PNG/BMP formats cannot be saved in CMYK color mode, so they are not suitable for printing.