Can letter-spacing be set to very small values?

Question

css

Good evening!
There was a need to lay out a web page according to a PSD layout exactly pixel-for-pixel. When I started to typeset one of the blocks, I decided to use letter-spacing to achieve the exact letter spacing.
Can you please tell me if it is common to use very small values ​​in letter-spacing? For example, to achieve accuracy with the PSD layout, I had to specify:

some-block {
    letter-spacing: 0.017em
}

Is this normal? Are there such cases in practice?
- - - - -
And the second (following) question. Can letter-spacing be used in negative values?
For example, there is a place where the text is longer than in the layout. I specified letter-spacing: -0.003em and everything was fine. is this practiced?

Answer 1

The answer is "yes" on both counts.
But generally speaking, it is not necessary to pursue absolute compliance with psd, since Adobe font rendering is by definition different than in OS and browsers. If the difference is in thousandths - score. If the discrepancies are more significant, do not treat the symptom, but find out the cause.

Answer 2

You can set, but browsers can round off. Look at this layout in different browsers, on different operating systems, and with different settings for all sorts of improvers, such as cleartype. There is not much sense in such subpixel fuss.

Answer 3

Practiced in pixel perfect layout. Very often it is used when making up just from psd layouts. 50 tracking units in fsh is about 0.050em in css