Requests for curves for photo retouching
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| Requests for curves for photo retouching | Andrea Olivotto | 09 Nov 13:02 |
| Requests for curves for photo retouching | Sven Neumann | 09 Nov 13:37 |
| Requests for curves for photo retouching | Andrea Olivotto | 09 Nov 15:40 |
| Requests for curves for photo retouching | Sven Neumann | 09 Nov 16:35 |
| Requests for curves for photo retouching | Andrea Olivotto | 09 Nov 16:50 |
| Requests for curves for photo retouching | Alexandre Prokoudine | 09 Nov 17:02 |
| Requests for curves for photo retouching | jernej@ena.si | 09 Nov 17:06 |
| Requests for curves for photo retouching | Alexander Rabtchevich | 09 Nov 17:35 |
| Requests for curves for photo retouching | Stephane Chauveau | 20 Nov 00:52 |
| Requests for curves for photo retouching | Owen | 20 Nov 07:14 |
Requests for curves for photo retouching
Hello to everyone!
I'm Andrea from Italy, this is my first post.
I'm an amateur photographer, and I'm using GIMP to retouch my photos. I wrote some articles in italian on the argument, and I'm here to suggest some hints for this beautyful program.
Histogram:
- It's an invaluable tool for photo retouching, for valuating contrast, brightness, clipping (even channel by channel), posterization.
- Should be upgraded in real time, when doing levels, curves, ... (I know it done on the 2.4.1 release) better if during correction the original histogram is grayed in the background, and the histogram of the current correction is black in the front.
- Like other photo retouching programs (take a look to UFRaw), there could some checkboxes to enable clipping areas blinking. This is very useful to see clipping, even better if could be updated in real time during correction (as the entire histogram).
- Linked to the previuos hint, on the histogram window there could be shown the percentage of clipping towards the white e the black (see UFRaw).
Levels:
- When you pass the mouse over the current image, show in the histogram on the levels window the luminosity position, something like a small circle running thru the orizzontal line.
Curves:
- Please, a more dense curve. Better if user can select 4 or 8 lines.
- Please, draw in the background the baseline (45°). It's a very useful reference, more visible than looking to the vertex of the grid.
- Like levels, when you pass the mouse over the current image, show the luminosity position on the curve, something like a small circle running thru the curve (like Photoshop). This is very very very useful, to see where are some particulas ares of the image on the curve. Without the feature, it's not so simple to design a correct curve.
If you want to see some GIMP and Photoshop histogram, levels and curves
images, take a look to my articles (they are in italian, but the
important thing are the images):
http://www.andreaolivotto.com/photo_retouch_03.html
http://www.andreaolivotto.com/photo_retouch_04.html
http://www.andreaolivotto.com/photo_retouch_05.html
Thanks a lot in advance.
GIMP has the chance to be one of the best tool to retouch photos. It's already the best in the open source world.
Requests for curves for photo retouching
Hi,
On Fri, 2007-11-09 at 13:02 +0100, Andrea Olivotto wrote:
- Please, a more dense curve. Better if user can select 4 or 8 lines.
It would be nice if you could explain why the current grid isn't dense enough and how exactly a more dense grid would be useful.
- Please, draw in the background the baseline (45°). It's a very useful reference, more visible than looking to the vertex of the grid.
In my opinion this would be very distracting. I can imagine that a denser grid would also make it easier to see the diagonal. So perhaps just adding a few more grid lines would make this obsolete?
- Like levels, when you pass the mouse over the current image, show the luminosity position on the curve, something like a small circle running thru the curve (like Photoshop). This is very very very useful, to see where are some particulas ares of the image on the curve. Without the feature, it's not so simple to design a correct curve.
GIMP already does this. Just click into the image with the Curves tool active. Also try using the Shift and Ctrl modifier keys.
Sven
Requests for curves for photo retouching
Sven Neumann wrote:
Hi,
On Fri, 2007-11-09 at 13:02 +0100, Andrea Olivotto wrote:
- Please, a more dense curve. Better if user can select 4 or 8 lines.
It would be nice if you could explain why the current grid isn't dense enough and how exactly a more dense grid would be useful.
- Please, draw in the background the baseline (45°). It's a very useful reference, more visible than looking to the vertex of the grid.
In my opinion this would be very distracting. I can imagine that a denser grid would also make it easier to see the diagonal. So perhaps just adding a few more grid lines would make this obsolete?
The grid and the baseline are useful reference. Curves corrrections are very small, because small deviations from the baseline have great impact on the image change. So, when I made a simple S curve to increase contrast, I'm playing... within some pixels! A denser grid and a baseline is useful. I'm using Photoshop as well (check th figures of my article on curves http://www.andreaolivotto.com/photo_retouch_05.html), and when you are used to its curve window... I think it's a simple improvement. If you think it could be distracting (for an inexperienced used), make it configurable via two checkboxes.
- Like levels, when you pass the mouse over the current image, show the luminosity position on the curve, something like a small circle running thru the curve (like Photoshop). This is very very very useful, to see where are some particulas ares of the image on the curve. Without the feature, it's not so simple to design a correct curve.
GIMP already does this. Just click into the image with the Curves tool active. Also try using the Shift and Ctrl modifier keys.
Ops! I will try as soon as possible!
Many thanks again,
Andrea
Requests for curves for photo retouching
Hi,
you might want to have a look at http://sven.gimp.org/misc/gimp-curves.png which is a screenshot of the Curves widget from SVN trunk. As you can see we already incorporated some of your suggestions. And of course the widget benefits a lot from being drawn with Cairo...
All this is still open for discussion and will probably undergo further changes. Your input is appreciated.
Sven
Requests for curves for photo retouching
Sven Neumann wrote:
you might want to have a look at
http://sven.gimp.org/misc/gimp-curves.png which is a screenshot of the Curves widget from SVN trunk. As you can see we already incorporated some of your suggestions. And of course the widget benefits a lot from being drawn with Cairo...
It's very nice!
Could be perfect if you'll add the baseline.
All this is still open for discussion and will probably undergo further changes. Your input is appreciated.
Will the Cairo libray be ported in Windows? Or is a strict Linux library?
Requests for curves for photo retouching
On Nov 9, 2007 6:50 PM, Andrea Olivotto wrote:
Will the Cairo libray be ported in Windows? Or is a strict Linux library?
It's already ported and used by varios crossplatform applications for quite a while (e.g. Inkscape).
Alexandre
Requests for curves for photo retouching
On Friday, November 9, 2007, 16:50:58, Andrea Olivotto wrote:
Will the Cairo libray be ported in Windows? Or is a strict Linux library?
GTK+ has used Cairo since 2.8, which is why Windows 9x/ME support was dropped then.
Requests for curves for photo retouching
It would be nice if the curves dialog becomes semi-transparent when user clicks image if the dialog overlays the image. Currently the dialog size is so large, than it is hard to preview the whole image with the dialog not overlaying it at 1024:768 monitor resolution.
Some backward interaction would be nice to see too. I posted a feature request some time ago to be able to select some range (abscissa) at the curves dialog and to see the result blinking or other pixels shaded. That could help deciding curve editing.
Sven Neumann wrote:
Hi,
you might want to have a look at http://sven.gimp.org/misc/gimp-curves.png which is a screenshot of the Curves widget from SVN trunk. As you can see we already incorporated some of your suggestions. And of course the widget benefits a lot from being drawn with Cairo...
All this is still open for discussion and will probably undergo further changes. Your input is appreciated.
Sven
--
With respect
Alexander Rabtchevich
Requests for curves for photo retouching
Andrea Olivotto wrote:
Hello to everyone!
I'm Andrea from Italy, this is my first post.
I'm an amateur photographer, and I'm using GIMP to retouch my photos. I wrote some articles in italian on the argument, and I'm here to suggest some hints for this beautyful program.
Histogram:
- It's an invaluable tool for photo retouching, for valuating contrast, brightness, clipping (even channel by channel), posterization.
I just want to warn you that using the Curve tool for photo retouching
is not always a good idea because the so-called 'Value' curve is
nothing else than the same curve applied to the Red, Green and Blue
channels. In practice, that means the 'Value' curve does not preserve
the Hue and the Saturation at all.
The curve tool should be fine for small adjustments but for serious
works, you should prefer the brightness/contrast and
hue/lightness/saturation tools.
If you are not convinced then try the following: - Fill your image with a color composed of 100% Red, 50% green and 0% Blue. That should give you a nice orange. - Open the 'Value' curve and add a point in the middle. - By moving the 3 points of the curves (left, middle and right) up and down, you now control the Blue, Green and Red components of the image color. You should be able to produce all colors and when I say all I mean ALL: blue, pink, yellow, white, purple, black...
You will also notice that the 'value' reported by the curve when clicking in the image has little to do with the colors that are really affected by the curve: In my example, the initial color has a 'value' of 100% but it is affected by moving the left (value 0%) and middle (value 50%) points.
Requests for curves for photo retouching
Andrea Olivotto wrote:
Hello to everyone!
I'm Andrea from Italy, this is my first post.
I'm an amateur photographer, and I'm using GIMP to retouch my photos. I wrote some articles in italian on the argument, and I'm here to suggest some hints for this beautyful program.
Histogram:
- It's an invaluable tool for photo retouching, for valuating contrast, brightness, clipping (even channel by channel), posterization.
I just want to warn you that using the Curve tool for photo retouching is not always a good idea because the so-called 'Value' curve is nothing else than the same curve applied to the Red, Green and Blue channels.
Just select Colour->Curves->Channel value, select Red/Green/Blue or alpha if it exists and adjust.
Owen
