Basic histogram question

Supposedly you can hotlink to this image he
http://photoviki.com/albums/userpics/10196/Mittens.jpg

If not you should be able to get to it he
http://photoviki.com/displayimage.php?pos=-15138

When I loaded this image into Photoshope Elements the histogram was
shifted to the left. The reds were mostly in the middle to left, the
greens even more to the left and the blues even more left. What is
this telling me? Should an image like this, where I have complete
control of lighting and other things, have the histogram in the middle
in all colors?

Thanks,
Ron

wrote in message
oups.com...
Supposedly you can hotlink to this image he
http://photoviki.com/albums/userpics/10196/Mittens.jpg

If not you should be able to get to it he
http://photoviki.com/displayimage.php?pos=-15138

When I loaded this image into Photoshope Elements the histogram was
shifted to the left. The reds were mostly in the middle to left, the
greens even more to the left and the blues even more left. What is
this telling me? Should an image like this, where I have complete
control of lighting and other things, have the histogram in the middle
in all colors?

I think we need to go back to the basic question of what a histogram is -
it's a graph showing how many pixels (for each of R G and B) exist at each
tonal level (from darkest to lightest). If we don't want our images to look
flat then it's important that we use the full tonal range (ie the histogram
has some activity at both extremes of the horizontal axis).

If everything is shifted towards the left end of the graph then it's an
indication of the image being under-exposed. My understanding of individual
colours though is "providing most of the image is spread across the entire
graph (ie any colour) then seeing a peak at the lower ends simply indicates
that there's something quite dark that's made up with significant amounts of
that colour.

No-doubt others will re-educate me if I'd strayed too far in any of the
detail!

wrote in message
oups.com...
Supposedly you can hotlink to this image he
http://photoviki.com/albums/userpics/10196/Mittens.jpg

If not you should be able to get to it he
http://photoviki.com/displayimage.php?pos=-15138

When I loaded this image into Photoshope Elements the histogram was
shifted to the left. The reds were mostly in the middle to left, the
greens even more to the left and the blues even more left. What is
this telling me? Should an image like this, where I have complete
control of lighting and other things, have the histogram in the middle
in all colors?

Thanks,
Ron

The histogram is only a guide. If you take a photo of a ring against a
black background the histogram will move all the way over to one side. Same
if you take a photo of a black cat in a snowbank, it will shift to the other
side. So, when you say you expect the histogram to be in the middle of the
graph it depends on the image.