change 150 dpi

[mj.walker]

How to convert to 150dpi and keep layers in a 300dpi PDF file?

[Brad @ Roaring Mouse · Accepted solution]

A few ways.. (Assuming you already have layers). Here are Two:

You can apply a Preflight Fixit to do the downsampling for you. There's a built-in one to do exactly what you want.

 

OR

you could simply Save As Other > Optimized PDF and select a setting to resample your images to 150 for any image over 150.

Neither should affect the layering at all.

[mj.walker]

Apply a Preflight Fixit is OK

Thank you

[Abambo]

You can only influence the size/quality of image types (colour, grey, bitmap) but not certain images only.

Abambo
via mobile phone.