What are you thoughts on fractional sizes for font and leading?

Is this classically a big no no, or is it today generally accepted that you can use whatever you like in digital age?

I've done several test prints and Adobe Caslon Pro 9.5 pt on 12.5 pt leading fits my project the best. It's also the winner by blind test readers. 9/12 was elegant but too small, 9.5/12 was ok but a bit too tight and 10/13 where too big and spacious over all.

Will fractional sizes cause problems further in the project? I am using the leading as base for sizing most other things like white space and image sizes.

Do modern type designers take fractional font sizes in consideration when creating fonts? Or does it not matter, can the software scale fractional fonts just as good as non fractional? 

(I am using InDesign CC.)

41 minutes ago, Grotesk said:

generally accepted that you can use whatever you like in digital age?

If it doesn’t bother you in regard to your layout (e.g. baseline grid and so on), then “yes”. Regarding the design, it’s all about the actual visible letters, and their relation to the virtual bounding box is pretty arbitrary. 

Thanks for you input Ralf.

Yes, I understand that in the end it's all up to me. The computer doesn't care about what kind of units or sizes I use.

But as a human it can quickly get confusing and ugly with messy fractions.

Grotesk you need to be aware that back in the olden days of metal type, (when I started as a designer) we used actual pieces of lead, yes lumps of metal, to determine the spacing between lines, hence the term leading. These days we are freed from all those constraints. As Raff says all you have to worry about is "is it legible" can you read it?

I’ll agree here. Good design includes using appropriate type at appropriate sizes, with appropriate line spacing, column width, etc. And by “appropriate” I mean of course for readability by your intended audience/readership. No one (except nerds like us) notices the grid behind your layout. I confess, I often tend to choose traditional metal-type sizes to start with (I also go back that far), but fine-tuning usually takes me away from that old habit. I’ll confess again, discovering type that has been set at 9.675 point, for example, makes me cringe, but if that’s what works, there’s no rational reason to say no.