changing bg color of an already solid color...

Canon EF 70-300mm f/4.5-5.6 DO IS USM

06/06/2006 12:06:59 AM · #1

If i shoot a portrait against a completely white paper backdrop, is there a super easy way to make the white a different color without having to mask and all that?

cpanaioti

Canon EOS-40D

06/06/2006 12:08:55 AM · #2

If there's no white anywhere else in the image then selecting just the background is easy.

However, if the colour of your background appears somewhere in your main subject then your stuck with having to mask the hard way.

06/06/2006 12:45:19 AM · #3

quick explanation?

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/06/2006 12:47:22 AM · #4

This is what they designed the Magic Wand tool for : )

You might try using just one of the colors instead of the RGB channel if it offers a better contrast between subject and background.

06/06/2006 12:49:51 AM · #5

tutorial? or quick explanation?

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/06/2006 01:09:49 AM · #6

What software and Operating System are you using?

Canon EF-S 18-55mm f/3.5-5.6 IS

06/06/2006 01:11:18 AM · #7

With "selective color" adjustment layer in photoshop, you can change the color of the white BG to anything you want, if it is in fact pure white it's very easy.

Open up a selective color adjustment layer, click on the drop-down list for color channels, and select white. Play with the sliders to get the color you want. If nothing else in the image is white, you are in good shape. If some parts of your subject are white, you will need to select those areas; you can do it with the marquee tool or the lasso, the selection doesn't have to be precise. when you have everything that's not white BUT the BG selected, invert the selection (keyboard cntrl-shift-i) and THEN use a selective color adjustment as above on the inverted selection.

This is one approach.

Robt.

justin_hewlett

Canon EOS-1000D Rebel XS

06/06/2006 01:20:36 AM · #8

Originally posted by GeneralE:

This is what they designed the Magic Wand tool for : )

You might try using just one of the colors instead of the RGB channel if it offers a better contrast between subject and background.

To add to what GeneralE said:

The magic wand tool is designed to select all nearby pixels of similar color/tonality as the one clicked. With this tool you are able to set the tolerance, where high tolerance picks up more similar colors (is less restrictive) and a lower tolerance picks up less similar colors (more restrictive). I suggest you mess around with this tool, and observe the effect of tolerance on the selection. The default tolerance value, 32, is often a good staring point.

Once you have your selection, you can then modify it to perfect it. You could click on the lasso tool (or other selection tool) and then use shift+click-and-drag to select a portion to add to the selection. Use alt+click-and-drag to select a portion to delete from the selection. You'll want to completely encircle the portion (remember, using shift to add to it and alt to subract from it).

At this point you may want to feather your selection. Feathering "softens" a selection and will ease the transition from the portrait to the background - it will get rid of the hard edge. I would probably start with a value of 2-4.

When you have your desired selection, you can then use the [del] key to delete the selected pixels and then put a solid fill with the new color on a layer underneath. That way the color will show through the transparent pixels. Or, better yet, you could use that same layer underneath, but instead of deleting the contents of your selection masking off that portion. To do this, with your selection active go to Layers > Add layer mask. It should have the same effect as the above method only this method is lossless and you can always undo/change the pixels that are seen and which aren't.

That's the quick version. If you have any questions just let me know.

Message edited by author 2006-06-06 01:24:47.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/06/2006 01:42:45 AM · #9

Instead of feathering, save the selection. It will now appear as a new grayscale channel, and you can edit it with any of the normal painting tools. This allows you to zoom in and touch up the mask (same as thing as a selection, which is the same thing as an alpha channel) with extreme accuracy. Use a soft-edged brush to automatically feather the edges.

Once you have an accurate selection/mask saved, you can load it (or the inverse) to make all kinds of handy adjustments and edits.

If you are starting with a uniform BG, you can try setting the Magic Wand to a tighter tolerance -- I usually start at 4-8 and adjust from there. If you have discontiguous areas, you can shift-click with the Magic Wand, or use the menu iter Select > Similar to select everything within the photo of the same color, using the same tolerance setting as the MW; set that in the Options window.

06/06/2006 01:53:06 AM · #10

All of this advice for selection is very nice, but it's extraordinarily difficult sometimes to make a clean selection of an object from its BG. In cases like the one proposed, where the BG is pure white, it is often not necessary to make any selection at all, or at worst just simple, loose local selections to mask out any white in the subject itself. Then let selective color work its magic in a most seamless manner :-)

R.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/06/2006 01:53:16 AM · #11

Here's a screenshot showing a partly-completed mask I'm making to blur the BG behind the chicken.

06/06/2006 11:24:14 AM · #12

Originally posted by Bear_Music:

Wouldn't it just be easier to paint back on the mask the parts of the person that were white to make them white again? I hate selection tools.

06/06/2006 11:28:05 AM · #13

Originally posted by specialk0783:

Wouldn't it just be easier to paint back on the mask the parts of the person that were white to make them white again? I hate selection tools.

Everyone has their own approach. The OP seems to be brand-new to this, and straight selection needs less explaining than masks/painting...

R.

Nikon AF-S DX Zoom-Nikkor 17-55mm f/2.8G IF-ED

06/06/2006 11:30:47 AM · #14

selective color is not working with whites selected.

I even put all the sliders at 100% and it just makes the person, who is tan, crazy colors and the white background has very little difference. This is on a flattened image by the way so no layers are in the way.

I used the magic wand at 30 tolerance and it makes a horrid selection, you can see the seperation from where the person is to the bg and it looks ragged and horribly laid.

I give up. I'm just going to go buy different colors of bg paper.

Message edited by author 2006-06-06 11:31:11.

Cutter

Nikon D700

06/06/2006 12:26:39 PM · #15

bear,

that it great advice. I am gonna try that.

TrynityRose

Nikon D100

Nikon AF Nikkor 50mm f/1.8

06/06/2006 12:39:40 PM · #16

Tutorial

06/06/2006 01:23:08 PM · #17

Originally posted by specialk0783:

I have done a quick makeover on one of your dog shots. I selected, purely for purposes of illustration, 3 horizontal bands across the entire image and using "selective color only" I changed the colors of the white to yellow, blue, and green respectively. In the detailed image, the dialogue box shows the slider positions for the blue section of the BG. Note especially that the box for "absolute" is checked ("relative" is default and it won't work). Note also that the halo around the dog exists on your original; it's not an artifact I created in this workflow.

To recap; I could have made the white BG any of these 3 colors (or any other color for that matter) without doing any selection at all: the only purpose for the selection of the horizontal bands was to get three BG colors in one image to show you a range there.

Your complaints about using the selection tools to "grab" the white BG are well-founded; it can be extraordinarily difficult to do a good job, depending on the smoothness of the separation of BG and subject. It can be done, of course, but it takes a lot of practice to do it well. This selective color technique works very well if you have a pure white BG, but pretty much ONLY if you have a pure white BG. It's really of more relevance in showing how versatile "selective color" can be in affecting the colors of an image.

R.

Prof_Fate

06/06/2006 02:01:20 PM · #18

take the LEVELS dialog and click on the rightmost eyedropper, then click on the white BG in the image.

now take the magic wand, set the tolerance to something very low - 2 maybe, certainly less than 10. click the white BG area.

Select-Modify-Expand - expand 1 or 2 pixels - this eliminates the halo
Shift-Crtl I (inverts the selection)
Ctrl-J (creates a new layer from the selection)

you now have a foreground layer and the orginal - insert a layer inbetween of the new background - be that a photo or a fill layer of a solid coolr, generated clouds, gradient, etc.

this was done with a black background -
the original:

and the one click alternative (sunset shot in the BG)

Message edited by author 2006-06-06 14:02:34.

Canon EF 24-70mm f/2.8L USM

06/06/2006 02:13:42 PM · #19

Not to pick on you or anything (that's a decent quick version), but take a look at the magnified section of your composite, below: see the jagginess of the selection area in the center? That's what he's complaining about, and there's no way around it that I've found but careful, even meticulous, handwork. And the problem gets even worse when your subject doesn't have a clean, smooth perimeter; as, for example, a headshot, where it can be fiendishly difficult to deal with hair naturally.

Robt.

J_Ehrat

Canon EOS-5D

06/06/2006 03:21:47 PM · #20

This is a link to a great tutorial video on making difficult selections.

Radiant Vista Tutorial

justin_hewlett

Canon EOS-1000D Rebel XS

Canon EF-S 18-55mm f/3.5-5.6 IS

06/06/2006 08:07:27 PM · #21

Originally posted by Bear_Music:

That's what he's complaining about, and there's no way around it that I've found but careful, even meticulous, handwork.

Methinks a slight feathering would have helped as well.