It can be. You can merge 2 layers leaving other layers. Merging all is flattening, that is, producing an image file with only one layer. So exporting to png or jpeg is flattening since these formats only support one layer.
Although in Gimp the layers dialogue menu has a Flatten function. This removes all transparency so do not use that. Similar to exporting to a jpeg.
You need a single layer with transparency? then merge all layers and export to png or maybe psd format.
edit:
The other thing to remember when printing is, there is no white ink. Any white in your image is the colour of the paper. You will only need transparency if it is partial transparency.
Although in Gimp the layers dialogue menu has a Flatten function. This removes all transparency so do not use that. Similar to exporting to a jpeg.
You need a single layer with transparency? then merge all layers and export to png or maybe psd format.
edit:
Quote:..I have three illustrations that will be on cream color paper so I need transparency in my images and I can’t find a way to have both transparency and flatten in my image....
The other thing to remember when printing is, there is no white ink. Any white in your image is the colour of the paper. You will only need transparency if it is partial transparency.