Imagine that you draw a curve on graph paper or squared paper with a soft pencil. At the moment, it's a smooth curve with sharp edges. If you rub your finger along the line, it will become blurred. For the 'low resolution' version, draw another line that must be as close to the curve as possible but using only the lines printed on the paper. This still has sharp edges, and is still similar to the original curve, but contains less information. Does that work as an analogy? In low-resolution photos, the detail that is lost tends to be in things like fine lines and subtle differences in colour, although I can't speak for other people's eyesight.
For the record, I'm long-sighted. My vision is normal to within a few inches of my nose, although it takes more work to focus on anything within arm's length. If I'm tired, detail becomes harder to see but I've never thought about how to describe the difference.
Er... I'm actually not sure it does make sense. Are you saying that, when you're looking at low-resolution photos, you're seeing less, but what you do see is still clear and sharp? (Is trying to wrap her head around low-resolution images, and failing spectacularly...)
It can be; it depends, I'm afraid. It often looks different to problems with focus but the result can't always be described as 'sharp'.
The problem with low-resolution pictures is that, to save space, the 'original' picture is approximated with small squares of colour. In small pictures, or from a distance, the difference may not be too noticeable to the naked eye. The more you enlarge the picture, however, the more obvious the differences become, and you may see things like complicated black and white tracery depicted as a series of gray squares, or a gradient of colour approximated with a couple of squares of one shade followed by a couple of squares of a lighter shade. At a distance, some of this may look like 'blurriness' but it's not usually as consistent a blur as a blur caused by focus; 'grainy' might be a better word.
This page (http://www.printingforless.com/resolution.html) contains a sample of text at two different resolutions. You may want to save the .gif files and play around with enlarging them if that makes it easier to see the difference. Neither will be perfect but the letters on the higher resolution picture should have better edges.
Hm. See, looking over that page, I'd describe the lower-resolution images as blurry. Grainy works, though, but I'm still not sure I'm getting it.
I don't mean to keep bugging you, but maybe you, or another interested party, could explain what the difference between focused and unfocused is? (Sounds kinda weird, coming from me, but it might help me grasp the difference between bad-focus blurriness and low-resolution graininess.)
I'm sort of running out of words, here. If this doesn't work, maybe someone else could have a go?
If you took the low resolution picture on that website, a perfect representation of that text (where there would be black, white and clear curved lines) and a version of the perfect image but with focus blur, and enlarged them until half of an 'n' took up the whole screen*, I think you should see:
'Perfect image': still only black and white, and a sharp distinction between the two. Parts that should be curved are perfect curves.
'Focus blur': black, white, and grey. Lines that should be curved are still curved. There is a perfectly smooth and even gradient from black to white around all edges.
'Low-res picture': black, white and grey. Lines that should be curved are in fact made up of blocks. There is grey around the black but (again) in solid blocks, and probably not evenly around the edges. Grey is used to get 'smoother' curves by filling in gaps around the black blocks.
*I'm assuming a 'perfect' screen here for example purposes
Okay, I think I get it now. The unfocused image is actually blending from one part into another, and the low-resolution image is, hm, actually sort of missing bits at the edges that would be there in the perfect image? Do I have that right?
Thank you very much for putting up with my questions. I know I'm being a bit of a nuisance...
Pretty much. Sometimes the 'bits missing' are colours, so that a smooth shading from blue to green can become a small block of blue, followed by a greener block of blue, followed by a block of turquoise, etc. It's basically an approximation of (what we percieve to be, but in fact is not) a perfect image. If the 'blocks' are larger and the number of colours are fewer, the resolution is said to be reduced and the image is more distorted.
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Date: 2007-01-16 04:27 pm (UTC)Imagine that you draw a curve on graph paper or squared paper with a soft pencil. At the moment, it's a smooth curve with sharp edges. If you rub your finger along the line, it will become blurred. For the 'low resolution' version, draw another line that must be as close to the curve as possible but using only the lines printed on the paper. This still has sharp edges, and is still similar to the original curve, but contains less information. Does that work as an analogy? In low-resolution photos, the detail that is lost tends to be in things like fine lines and subtle differences in colour, although I can't speak for other people's eyesight.
For the record, I'm long-sighted. My vision is normal to within a few inches of my nose, although it takes more work to focus on anything within arm's length. If I'm tired, detail becomes harder to see but I've never thought about how to describe the difference.
no subject
Date: 2007-01-17 10:41 pm (UTC)no subject
Date: 2007-01-18 10:50 am (UTC)The problem with low-resolution pictures is that, to save space, the 'original' picture is approximated with small squares of colour. In small pictures, or from a distance, the difference may not be too noticeable to the naked eye. The more you enlarge the picture, however, the more obvious the differences become, and you may see things like complicated black and white tracery depicted as a series of gray squares, or a gradient of colour approximated with a couple of squares of one shade followed by a couple of squares of a lighter shade. At a distance, some of this may look like 'blurriness' but it's not usually as consistent a blur as a blur caused by focus; 'grainy' might be a better word.
This page (http://www.printingforless.com/resolution.html) contains a sample of text at two different resolutions. You may want to save the .gif files and play around with enlarging them if that makes it easier to see the difference. Neither will be perfect but the letters on the higher resolution picture should have better edges.
no subject
Date: 2007-01-18 11:06 am (UTC)I don't mean to keep bugging you, but maybe you, or another interested party, could explain what the difference between focused and unfocused is? (Sounds kinda weird, coming from me, but it might help me grasp the difference between bad-focus blurriness and low-resolution graininess.)
Thank you. That's a useful site.
no subject
Date: 2007-01-18 04:42 pm (UTC)If you took the low resolution picture on that website, a perfect representation of that text (where there would be black, white and clear curved lines) and a version of the perfect image but with focus blur, and enlarged them until half of an 'n' took up the whole screen*, I think you should see:
'Perfect image': still only black and white, and a sharp distinction between the two. Parts that should be curved are perfect curves.
'Focus blur': black, white, and grey. Lines that should be curved are still curved. There is a perfectly smooth and even gradient from black to white around all edges.
'Low-res picture': black, white and grey. Lines that should be curved are in fact made up of blocks. There is grey around the black but (again) in solid blocks, and probably not evenly around the edges. Grey is used to get 'smoother' curves by filling in gaps around the black blocks.
*I'm assuming a 'perfect' screen here for example purposes
no subject
Date: 2007-01-19 12:15 am (UTC)Thank you very much for putting up with my questions. I know I'm being a bit of a nuisance...
no subject
Date: 2007-01-19 10:06 am (UTC)no subject
Date: 2007-01-19 10:08 am (UTC)