Fantastic application and some histogram questions . . .

[SJ9000]

Hi all,

First, I want to congratulate the Huber's for a great application -- it's fantastic.

I've just started working with the evaluation version(17.52 ) of Photoline for 2 weeks and have some questions. Is there any way to view individual channels in the Histogram panel? Also is there any way to turn off the smoothing effect? I'd like to be able to see just the 256 levels. Right now I see gradations between the data, and when I'm trying to evaluate images it's difficult to know if it's data or "smoothing". Could this be an option?

Also with the Histogram panel, is there anyway to display more data? Such as total number if pixels, an index of the 256 shades as you mouse over the histogram, And how about average, mean, and median?

And a wish I've always had is to be able to create a mask based on the histogram. So maybe if you hold down the right mouse button and drag through the histogram PhotoLine makes a selection from the selected range. Is that possible?

Well, that's it for now. Again thanks for a great application. You guys are amazing!

SJ9000

[gmhofmann]

Right click in the histogram window: You can choose between "all layers" and "active layer"

[bkh]

Also with the Histogram panel, is there anyway to display more data? Such as total number if pixels, an index of the 256 shades as you mouse over the histogram,

Have a look at the histogram displayed by the "Histogram Correction …" adjustment layer (use the chain symbol to get a histogram an individual layer, otherwise you'll get a display of the combined layers below). There, you can choose individual channels and get raw pixel counts while you move the cursor through the histogram. You can even switch to a different colour model there. The diagram itself is smoothed, but like the other histogram, the display is fine enough to see gaps. I mostly use this adjustment layer if I need to view the histogram. Might be nice to have the same features in the normal histogram as well.

And how about average, mean, and median?

Not available, afaik. Btw., average and (arithmetic) mean are the same. (But if the developers consider adding this information, then please also add std deviation and quartiles!)

And a wish I've always had is to be able to create a mask based on the histogram. So maybe if you hold down the right mouse button and drag through the histogram PhotoLine makes a selection from the selected range. Is that possible?

I'm not sure what you need this feature for – there are several similar possibilities in PL (Automask, Select Colors …). You could also create a soft mask from a colour channel and use "Threshold" on the mask (in mask edit mode). If you want to create a layer mask based on channel values, then "Colour Filter …" might be the best way to go.

Cheers

Burkhard.

[greenmorpher]

And how about average, mean, and median?

Not available, afaik. Btw., average and (arithmetic) mean are the same. (But if the developers consider adding this information, then please also add std deviation and quartiles!)

Not forgetting the mode, of course!

Cheers, geoff

[SJ9000]

Hi guys,

gmhofmann: Thanks for your quick response, but I was wondering about channels (RGB, CMYK, Lab), and not layers. I want to be able to evaluate the data in each individual channel -- thanks anyway.

bkh: Thanks for you're tip about looking at the "Histogram Correction …" adjustment layer. That helps a lot. Still it would be nice it it were part of the histogram panel ( or the Picture Info panel ) -- along with all the other stats. As for why it would be nice to select a range in the histogram, image you have a large gap it the tones, if you could redistribute the humps and gaps by dragging sliders -- well that would be cool. Maybe that could be done in the "Histogram Correction..." panel if it allowed more than one intermediate "gamma" point. That could work. What do you think?

On to another question. I have a gray scale layer and want to turn it into a selection. How's the best way?

Thanks,

Steve

[Hoogo]

On to another question. I have a gray scale layer and want to turn it into a selection. How's the best way?

You can switch to the tab "channels" in the layers list. At the bottom you find a button to create a mask from the active channel.

BUt if you want to use the mask for some adjustments, you might be happier when you just turn the layer into an adjustment layer. Use "view > panels > adjustment layer" for that.

[bkh]

As for why it would be nice to select a range in the histogram, image you have a large gap it the tones, if you could redistribute the humps and gaps by dragging sliders -- well that would be cool. Maybe that could be done in the "Histogram Correction..." panel if it allowed more than one intermediate "gamma" point. That could work. What do you think?

Well, I don't usually adjust tones by looking at the histogram (I prefer Curves because you can adjust tones directly) … but in a sense, you can also flatten a histogram by using Curves. Make the curve steeper where there are high counts in the histogram, make it flatter where there are low counts (you also have a histogram in Curves). The histogram correction below is just to show the output histogram.

curves.png

On to another question. I have a gray scale layer and want to turn it into a selection. How's the best way?

You probably want to turn it into a mask, in PL's terminology. "Selection" refers to the part of an image layer selected by such a mask, and the lasso is the line around a selection (or, more precisely, the line where the mask reaches 50 %).

Anyway, there are several possibilities: Shift-click on the preview icon in the Layer panel, use the icon on the lower left of the Channels panel, use "Change Channels" to copy the grey channel to the mask. If the greyscale layer is actually a layer mask (best way to store a selection!), you can use Layer -> Layer Mask -> Apply to Mask.

Cheers

Burkhard.

[SJ9000]

Thanks Burkhard,

As usual your reply helped me learn more about the ins and outs of PhotoLine. Thanks. And of course curves is a much better tool for adjusting tones than a histogram display, but for quick and dirty adjustments it wouldn't hurt to have such a simple tool available, and probably wouldn't be too difficult to add to PhotoLine.

And another question:

If there's a lasso or mask active, shouldn't the histogram show only the image data included in the selection? As far as I can tell, the histogram always displays data for the whole image. Is this true? If not, how do I see a histogram of just the data in a selected area? -- other than by cropping it temporarily -- and that won't work for a non-rectangular selection anyway.

Thanks,

Steve

[bkh]

If there's a lasso or mask active, shouldn't the histogram show only the image data included in the selection?

Probably a good idea. The histograms in "Curves" and "Histogram Correction" already behave in that way.

If not, how do I see a histogram of just the data in a selected area? -- other than by cropping it temporarily -- and that won't work for a non-rectangular selection anyway.

I'd probably use the histograms in "Curves" or "Histogram Correction".

Cropping (using a lasso tool) works with non-rectangular selections as well. Or make a (merged if you want all layers) copy of your selection. In principle, you could also convert the mask to a layer mask (Layer -> Layer Mask -> Create from Mask), but the vertical axis of the resulting histogram isn't scaled properly – with a small selection, you can hardly see anything.

Cheers

Burkhard.