Originally Posted by FitzRoy
Yeah... you applied a thick layer of noise to the image which looks nothing like real grain. You're just trading blurriness for fake definition and it shows.
It was not an attempt to look like 'real grain'. It was not a serious attempt at anything since it was knocked up in a few seconds on my browsing machine.
It was simply an illustration of an visual trick - when you add pixel-size artifical grain (in this example I used a crude noise filter because it was all I had handy on my browsing machine), it tricks the eye into seeing more detail than is really there.
If I spent a few more minutes doing something properly, I guarantee I could post it on a lesser forum and for sure some people would say "oh yes! looks much better and with more detail!"
In the industry, it is a well known phenomenon. It is primarily used when creating a HD release from an older digital scan that did not resolve grain well in the first place.
If you are already aware of the phenomenon and its use then you don't need to comment. The example was not an attempt to 'do it properly' rather just a quick illustration.