Photo ReColoring, Luminosity & You

[Ikean]

Okay, I'll start by introducing myself as a fairly decent photoshop user. I have been using PS for years and I'm okay, but I also know what the real photoshop gurus are capable of. (Which is why I'm here!). I have this problem that has irked me for a long time now, I've never found a solution nor have I seen what I'm about to describe decently done. Colorizing a photo can be fairly simple using Adjustment layers and Hue/Saturation, what I've never been able to do though, was convert black to white within a photo. The other way around, white to black, is fairly easy to pull with decent and satisfactory results. Black to white on the other hand, seems to give a lot of trouble in maintaining proper and believable luminosity. If I have a black plastic object, for example, that I'm attempting to turn white... through all random experimentation I have done the object either becomes another 'material'... ie. metallic, or the object becomes too washed out (loses detail) to even make the eye believe the change is real and the material is still the original. I do know, though, that people are capable of creating the illusion of all sorts of material and surface through photoshop. So, if someone has an idea on how to 'colorize' and image while maintaining the original and proper reflection of light on the surface of the object, I would LOVE to hear from you!

Here are some quick examples: (dont know how to post images on this forum)

Original image, plastic boot
http://img.photobucket.com/albums/v4...oot_normal.jpg

Attempting to lighten plastic center plate using levels, loses correct material luminosity and becomes metallic
http://img.photobucket.com/albums/v4...t_metallic.jpg

Attempting to lighten plastic center plate, using Lightness/Saturation, loses vast amount of surface detail, becomes 'flat' and washed out
http://img.photobucket.com/albums/v4..._washedout.jpg


Sooo...... How can it be done! Ideas? Solutions! Thanks =)





*edit* I'd also like to point out, that while attempting to do this, you will find many times the new white piece will have awkward (inverse) black 'reflections'... you can kind of see it in the last image a bit

[cducasse]

I inverted the image, and colored it...it needs work, but get the idea?

Sorry so rough...took about a minute...

[Lasa]

I don't know if you are a member of NAPP magazine but..
Sept 2003 edition they had a Digital Camera Workshop where they turned a black Mizuno shoe white..page 60/61 by Jim DiVitale

The short and sweet of it was:
Select the shoe.
duplicate the shoe layer and set to screen.
duplicate that same layer 4-5 time (always set to screen mode)
Then add a hue/sat adjustment layer lower saturation to -100%
Add a Burn+Dodge softlight layer (50% gray) paint with white to lighten black to darken.
add another blank layer. Select shoe, paint it with a light beige lower opacity to 24%

I gave it a rough test and it looked pretty good.

But then again if you do as Cducasse did invert..duplicate and set the dup to screen...looks pretty good also.

good luck,

Lasa
Lasa

[Lasa]

Here a play on invert using the curve adjustment that might help you...
the white looks good then mask out the shoe laces, rivits and rubber soles..
I think it might work...easier.
Lower saturation and paint over it...I got to run but I'll give it a try later. hope it helps.

Lasa

[edgework]

The best tool for color moves, when there is a reliable sample of the target color range, is the gradient map. It retains the original greyscale profile, but only as a reference, remapping complete colors from the new gradient. This allows you to set a completely new shadow and highlight, as well as control the tones in between, but the "shape" of the original remains.

After the gradient map, I pulled the range apart slightly with a contrast curve in luminosity mode, then a color layer at about 30% to help balance the hue.

[Lasa]

Edgework I used the gradient map but used dif two white diff sample taken from the from rubber sole for the map..after dodge/burn to mix them in better..same idea.

I didn't understand that they only wanted the plastic thingy..not the boot.

My bad,

Lasa

[Panpan]

Inverting the image doesn't work because it gives an unnatural lit-from-below look.

The part that you want to whiten is shiny. That means even though it's black, it has a high dynamic range. When whitening it, the shiny part won't change much so the solution is to lighten and to compress dynamic range at the same time.

A simple curve adjustment is good enough to do both, I think. You can adjust how white/black it is by adjusting the end of the curve and how plastic/metallic the shine is by adjusting the middle.

Pierre