Well, if a pixel is visually perceivable by eye, then the system has failed miserably in its very basics. I'm not saying that doesn't happen. It's actually one of the facts that separate theoretical and realistic digital imaging; even today, digital displaying on screen has not made a single step in last 10 years and this is one of the big reasons why digital pictures look oversharp, lacking detail, and film scans look overgrainy and/or blurry when shown on computer screen. But in theory, the idea goes that the pixel size is decreased until it is invisible to eye as a single pixel. This idea is actually somewhat close to that of a single "grain" or "crystal" or whatever in film, except that more grains/crystals than one are needed to render tones. In both cases (digital/film), the system is (or "should be") designed so that eye does not have enough resolution to resolve single grains/pixels. In digital, this "blurring" or combination process happens in two dimension, in film, it happens in three dimensions, and the third dimension prevents even electron microscope from seeing individual grains/crystals. But even if you cannot see them, they are there, and they can be seen indirectly, and understanding them is crucial. Furthermore, understanding is so easy that I find there is no reason to "hide" the construction of grain under typical internet statements like "there are no individual grains". (This is not a quote from you; it just came to my mind. We should actively try to smash internet legends every time we have a possibility to! .)
I agree that the naming conventions are very confusing and "grain" indeed can mean both things, but I did't like the fact that you first presented as if the OP had something wrong while he didn't, but was just using one of the usual naming conventions you just didn't happen to like. Distinct crystals/grains exist and you could have just said that, accompanied with an addition that they are not necessarily called grains.
After all, understanding that the individual grains/crystals exist, and their shape, is a prerequisite to further understand how their composites look like; how the individual grain size is related to RMS granularity (the first causes the second, with other factors too of course); and especially, as we are discussing emulsion making, we are making those individual crystals. On this subforum, crystal size and shape play a HUGE role --- we would use the RMS granularity for the opposite direction, trying to deduce the average crystal size based on that.
On the terminology side, calling them crystals should be quite safe and misconception-free. I'll try to use that word from now on, and "graininess" for the overall composite effect. This way, the ambiguous word "grain" can be avoided completely.
As a bottom line, getting information available and elaborating on the world behind the basics is more important than what terminology we use. And, luckily, this disagreement in terminology has been good for that purpose.
Last edited by hrst; 05-16-2012 at 03:07 PM. Click to view previous post history.