Photobook printing – does the text get printed differently?

Question

I've printed a few photobooks through various services (AdoramaPix, Blurb, etc.) and am always looking for better quality options. I hear good things about BayPhotos and Milk, in particular their 6-colour print. Unfortunately they don't seem to provide the option to design the pages with my own software. I'm thinking I could ignore this apparent limitation and create pages in Indesign and place them as full spread "photos" with their mandatory software.

My doubt is the following (besides not knowing the exact bleed etc. dimensions): if I add text to a layout and export the page as a jpg or tiff with sufficient resolution, will it make any difference in the printing of text compared to their recommended way of placing images and text as separate objects?

I am not familiar with printing technologies but I can imagine that text is sometimes printed in a separate process from images, and perhaps it results in sharper or otherwise better text rendering than treating it as mere pixels like any other photo. Am I overthinking this?

Answer 1

Computer generated text has sharp and smooth edges because the pixels at the edges have a computed opacity. This is (abusively) called "anti-aliasing".

If you put the text in your photo, it becomes a bunch of pixels and its size will change if the photo is scaled for printing (which is often the case). Scaling a image is done by interpolating pixels (i.e., a pixel in the result is a "blend" of pixels around its corresponding position in the source). The scaling algorithm doesn't know that the edge pixels are anti-aliasing pixels and applies the same interpolation algorithm than on the image.

Interpolation always introduces a slight blur so the text can become blurry. The image can be sharpened to eliminate the blur bu the high-contrast edges of text will often "over-react" and show artifacts. So, either way, the text edges are no longer smooth and clean and our eyes are rather good at noticing this.

By contrast, if the text is kept separate from the image, it can be kept as text data, and rendered at the final size after the image has been scaled for printing, so its edges are not subject to degradation. In some printing processes they could even use techniques similar to sub-pixel rendering.

So in theory keeping the text separate can give better results. But that could depend on the actual print process, and maybe the edge degradation can be lived with anyway.