Correction Challenge: Curves?

[Scottes]

OK, here's an image that seems like it needs curves to me. The orange really glows unnaturally - the butterfly in real life isn't as neon as this one appears. The green seems a touch bright, but the purple looks correct to me. Those are my thoughts - if you think different let me know.

This seems like the fix would use Curves, but I don't understand them too well. If you fix this with curves try to explain how you did it. A capture of the curves screen might be helpful. Of course, if there's another way let me know!

http://www.itsanadventure.com/postimages/butterfly2875.jpg

[Meerkat17]

Fist I masked off the butterfly and used the red and green channels of the curves to reduce the amount of orange. I checked one of my books on butterflies for a colour reference I think I've got it close enough to that.

I reversed the mask and decreased the saturation on the background by about -10. Using the curves and all three channels RGB I played around till the had the flowers more or less back to the original colour making sure that the leaves stayed almost the same.

I didn't take a screen grab of the curves - I did intend to but closed them before thinking! Sorry :oops:

David

http://www.btinternet.com/~David.Lewins/g5/images/butterfly2875_2.jpg

[Bytes U]

Like everything else in PS there's more than a couple ways to acheive similar results. I took your picture, new layer... select colour range, image box... eyedropper to deepest orange... back to selection button and slide the fuzziness button over to about 149, CTRL+U... adjust saturation of selection about -17.

This method you only change the butterfly and leave the rest of the photo as is.

http://4tg.ca/cf/butterfly2875-canonforum.jpg

[PacAce]

The thing that makes this photography difficult is the fact that direct flash was used and that's why the butterfly seems to have come out over saturated in color. But the truth of the matter is, butterflies are supposed to be iridescent under bright light. So, how to fix it? Here's my go at it.

http://www.tanseikai.com/tanseikai/images/others/butterfly2875_B.jpg

And my rather convoluted way of "fixing" it.

First I took a look at the histogram with all channels showing to see how the colors were distributed. I wanted to lessen the brightness of the orange and a little of the green without affecting the purple flower. Here's a link to my starting screen:

http://www.tanseikai.com/tanseikai/images/others/Step_1.jpg

Now, I bring up the levels panel and set the channel to RED and adjusted the output level (white side) so that the butterfly isn't so bright.

http://www.tanseikai.com/tanseikai/images/others/Step_2.jpg

Next, I switched to the GREEN channel and adjusted the output so that the green leaves looked just about right.

http://www.tanseikai.com/tanseikai/images/others/Step_3.jpg

Then, I went back to the RED channel to adjust the butterfly color again since adjusting the GREEN channel had a effect on the butterfly as well. I adjusted the middle value of the input level to get the color just right.

http://www.tanseikai.com/tanseikai/images/others/Step_4.jpg

At this point, we have a little too much blue in the picture so I switched to the BLUE channel and adjusted the middle input level to get the right balance of blue again.

http://www.tanseikai.com/tanseikai/images/others/Step_5.jpg

We're now done with the level so click OK to exit the levels panel.

And now for the final touch, I desaturated the colors a tad for a more natural look.

http://www.tanseikai.com/tanseikai/images/others/Step_6.jpg

And adjusted the contrast to finish off the image.

http://www.tanseikai.com/tanseikai/images/others/Step_7.jpg

[BigRed450]

Selective color>red channel >black slider +5

http://users.air.on.ca/cbjaps/butterfly2875b.jpg

[Jesper]

Here is my version...

http://home.hccnet.nl/jesper.de.jong/images/butterfly2875-jesper.jpg

This is what I did in Photoshop CS:

Select / Color Range. Clicked on the wings to select them. Set Selection Preview to Black Matte, to be able to see properly what gets selected. Set Fuziness to 175 to get as much orange selected as necessary - not all the way to 200, otherwise, a bit of the background also gets selected.

Select / Feather. Set Radius to 2 pixels. This is to make the edges of the selected area a bit softer.

With the butterfly selected, Image / Adjustments / Hue/Saturation. Set Saturation to -15 to make the orange a bit less radiant and Lightness to +10 to avoid making the wings much darker.

Select / Deselect.

Image / Adjustments / Curves. I'm going to use Curves to make the background a little bit darker (since you said the green was a little too light). You asked about using Curves. You can use Curves to correct colors, but IMO it's most useful as a way to accurately control contrast and brightness. I used this curve:

http://home.hccnet.nl/jesper.de.jong/images/butterfly-curves.gif

There are two control points: one on the bottom left, to bring down the darker shades a little bit, and one on the upper right, to keep the lighter shades the same.

Curves is not so difficult to understand. The curve is like a mathematical function. On the horizontal axis, you see the brightness range of the input image, from black to white. On the vertical axis, you see the output brightness. The curve maps brightness levels from the input image to brightness levels in the output image. For example, in my image of the curves dialog, you see "Input: 193" and "Output: 191" below the curve. That's the mapping at the control point I selected (the upper-right one): pixels with brightness 193 in the image are changed to get brightness 191 after applying the curve.

There are certain characteristic curve shapes that do certain things. For example, an S-shaped curve, like this, gives the image more contrast:
http://home.hccnet.nl/jesper.de.jong/images/curve1.gif

And an S-shaped curve rotated 90 degrees lowers the contrast in an image:
http://home.hccnet.nl/jesper.de.jong/images/curve2.gif

[Scottes]

Thanks folks!

What a variance in processes. No wonder people get overwhelmed with PS.

Now I have to find time to play with this stuff. I started this challenege and I haven't even been able to have a go at MediaMagic's image. It certainly is interesting watching the variations comes through.

I do a lot of programming in Perl, and Perl Hackers have a saying: TMTOWTDI (pronounced "tim toady") and it means There's More Than One Way To Do It. PS fits that saying well.