Matching Colours in Image Set

[carstenw]

I have several outside images shot on the same day, but in different directions and times of day. The result is that the sky and the lighting are always a little different. I have done first pass on the processing of the set, but I see now that the sky matches poorly, which might be a problem for the coherence of the set as a whole.

How does one go about matching the colours of items in individual shots without losing the rest of the colour work in each image?

Is this when I finally have to learn about what everyone means when they start talking about Photoshop layers?

Thanks in advance for any and all answers.

 

[Dale Allyn]

Carsten, this is definitely a good place to use layers.

If the scene allows, I understand the color adjustment tool in C1 will now allow one to select a color range and modify it, but that would only apply if your skies were the only part of the image with that color range. As you can tell, I don't use this tool in C1.

In PS one can duplicate the background layer, modify it's sky colors (by any of several means), and then mask the areas of the image which are not needed to be changed. It's not complicated, and in fact one of the more "entry-level" processes in PS. What I mean by that is that it's not something to avoid because of being too complicated.

 

[Corlan F.]

Best tools for that is probably from Nik Software, e.g. Vivenza.
Works like a breeze for the purpose. Was indeed originally designed for it.


edit: incidentally for those with NEF files, NX2 is a -more comprehensive- alternative. And more flexible / reversible since working on RAW files.

 

[carstenw]

Thanks for the Vivenza tip; I'll take a look at it. I am working with Sinar DNGs.

Meanwhile, I would prefer a solution which doesn't require a financial outlay and a new learning curve. Dale, I guess I duplicate the base layer opaquely, and then work on the new layer. Then I guess I need a layer mask? How do I paint in it selectively so that the transition is smooth? Does Photoshop have tools to help matching colours in various image parts, something like an image palette?

I haven't yet gotten so far into PS but I guess now is the time. Any links to tutorials are appreciated.

 

[Dale Allyn]

Hi Carsten,

I don't have experience with Vivenza, as Corlan has recommended, so don't want to suggest that PS is the only or best way. But here's a way that I would do it, pre-supposing certain image characteristics, etc., etc:

Open the image in PS...

Make adjustments to curves, hue/saturation, dodge/burn, etc. These adjustments would be on separate layers in my case. Opacity control of each layer is of significant value, so working in layers is much better than using "Image -> Adjustments -> whatever...

Click on "Background" layer in the layers palette. Duplicate this layer. Select this layer by clicking on it in the layers palette (probably already selected). Go to Image -> Adjustments... and modify hue/saturation or use any other adjustment appropriate to make the sky look correct. Ignore the other areas of the image.

Confirm that the "background copy" layer is selected in the Layers Palette. Click the Layer Mask icon at the bottom to create a mask. Choose the Brush tool (command-B). Set the opacity of the brush to 100% if you want to block out the changes to all areas other than the sky. Press the letter D to set the brush to "default" (black and white, not some other funky color). Black blocks out stuff in the layer, white allows it through. "X" toggles between black and white as the brush color. Make sure your brush color is black. (Using 100% brush opacity in this example, but might prefer several passes at a lower setting.)

Paint the areas that you don't want to have received the color adjustment (the landscape not affiliated with the sky). This leaves only the sky to show your color tweaks.

Once finished, you can then adjust the opacity of this layer (the background copy layer) to fine-tune the appearance.

Wow, that's a lot of rambling crap. There are some gaps there, and some blatherings. A bit much for a single post, esp. without screen shots. Sorry.

There are lots of online tutorials, as well as books for this, but I'll have to think about where the best links may be. To be honest, this is quite simple if we were sitting together, but a bit messy to write out without visuals.

One could also do this by other techniques, such as working on a duplicate image (rather than a layer) and then bring that in on a new layer, etc. But the above method is pretty straight forward and can produce good results.

Dale

Edit: you can control some of the smoothness of the transition b/n layers by choosing a softer brush. e.g. you might try a brush hardness of 35%. This, together with layer opacity, will provide a smooth transition.

Edit 2: if you prefer to PAINT IN the changes to the sky, you would want the initial mask to block out the layer (the background copy on which you tweaked the sky). You would then option-click the layer mask icon to add a mask which was filled with 100% black (or fill it with black from the edit menu). Then with all of your changes to this copied background layer blocked by the black fill, you would paint in the sky with a WHITE brush. The choice is usually dictated by the amount of work to hide or show the respective elements of the scene.

NOTE: the layer mask must be selected in the layers palette for the brush to function properly. IOW you want the MASK to have the border showing, not layer icon. This is the normal state if you add a mask, but if you find things not responding correctly, confirm that the mask is actually selected.

 

[carstenw]

That's brilliant, Dale, thanks for taking the time to write this out. I will try it when I find a little time, hopefully tonight. I have done some similar things before, but the problem is that I don't use CS4 that often, so I manage to forget bits. I will try to internalize this workflow for the future, since it is not the first time that I have trouble getting the colour right with primarily global adjustments. I have wanted to get into this direction for some time, but have put it off since I didn't really know where to start.

 

[Guy Mancuso]

Carsten can you not copy the settings of one image in your raw processor than apply that to others.

 

[carstenw]

Yes, but that is not what I mean. If I take two images with the sky included, one a little earlier when there was more sun, and one a little later, in another compass direction, one image might have more cyan in the sky than the other, for example. I find that when I tune my photos for the subject, the skies look quite different, from a purple cast through magenta to cyan. I need to make separate colour adjustments for different regions of the image to make the set as a whole look more coherent.

 

[Guy Mancuso]

Actually In C1 you could do that with Color editor with just picking the sky make those adjustments only and apply to others but have to be careful of any bleeding from the sky that is the same color in the regular part of the image which can be done just a little tricky. Otherwise layers seems to be your only option

 

[Corlan F.]

Carsten, i understand the cost issue OTOH the learning curve with PS layers and all can prove time consuming -and possibly frustrating.

For your specific purpose, I still suggest that you DL Viveza plug-in trial (no cost) for either PS, Aperture or LR. and try it. The sky area selections using U-Points, including optional blocking of similar colour areas is super smooth and easy.

Now, if you elect to use PS functions only, i recommend that for selection purposes you simply use the Select->Color Range menu item then play with the eyedropper and (single) slider value. It's an effective tool.
For exclusion of similar color areas outside the skies then use either ALT+Lasso Tool (super fast) or paint the masks as proposed by Dale (more precise but a bit slower technique).
In the latter case you want to use the Quick Mask button (last item bottom of the Toolbox) to switch from Selection to Mask mode. Just use the paint brush to your tastes** in Mask mode, then click again on the Quick Mask button.

Once your selection is completed, then preferably use the Adjustements Layer option with masks (from your selection). Much faster and easier to deal with than the multiple layer copies alternatives.


** re the mask edit paint brush, for this task normal settings are 100% opacity, flow and hardness. As Dale said, you can reduce hardness for transition zones -but only if really needed. Again, the Color Range function - Lasso tool should do the trick quite smoothly in your case. With super fast learning curve

 

[Jack]

My .02 is you have multiple questions here with no single answer:

If your shots are from different times of day and shooting angles, then sky color is going to change and the same scene will look different in reality anyway. Color temp is lowest at noon and higher at sunrise and sunset, and color temp affects ALL colors in your image, not just the sky. Here a good camera profile combined with a good white balance should give you accurate results though they may not appear visually coherent -- but they're accurate. As an artist you need to make a decision, do I want accuracy or continuity?

In the case where you want continuity, ie the sky to be identical in all of your images, my approach is to deal with that in the raw processor. In C1 this is easy by using the poorly-named skintone-dropper -- which should be called the accurate color dropper. Anyway, all I do is choose the sky I prefer and save that color to the dropper panel, then I can click the dropper on all other image skies and they will go immediately to the same color blue as the original. So now the skies are identical and all other colors fall where they may per the WB required to create the unified sky. You can accomplish the same thing in any other raw converter by proper choice of WB that renders the same color sky, though the process won't be as fast as the C1 accurate color dropper. Surprisingly, at least for most landscapes shot in the same general area at the same time of year, this approach of matching sky hue works very well for me, and I do not usually find the other color shifts troublesome.

However, there are situations where it skews other prominent colors in the image too far one direction or the other. Here is where you need to make localized color edits, which may have been your real question above --- and there are several ways to skin this cat. First one is in the raw processor. C1 has the color editor which is a very powerful individual color editor. Not sure what LR has now, but I suspect they have hue sliders, so you can probably make at least coarse adjustments to bring the colors other than the sky you just matched closer to your liking WITHOUT altering the sky.

The other method is CS and layers. Most of the time, I'd use a Hue/Sat adjustment layer for this. In it you choose the main color you want to edit, say green, then dropper the green you want to edit and it selects a swath of that hue. You can add or subtract adjacent hues by using the + or - droppers. When done with the selection, it may even add a new color definition to your list, like "Yellows 2" if the greens you selected were actually yellows. Anyway, now that's selected, you tweak hue and saturation to taste. You can perform similar edits using the Color Balance tool -- effective because it allows you to target shadow, midtone and highlight tones separately -- or the channel mixer for more global color changes. ALL of these adjustments can be further controlled by adding a mask and editing it to taste.

Hope this helps,

 

[Dale Allyn]

Lots of ways to approach it, Carsten. Some of it boils down to personal comforts/preferences. Also, we're only guessing at the type of adjustment range being sought, e.g. changing a gray sky to match a blue sky would be different than simply bringing two blue skies into closer harmony.

 

[carstenw]

Actually In C1 you could do that with Color editor with just picking the sky make those adjustments only and apply to others but have to be careful of any bleeding from the sky that is the same color in the regular part of the image which can be done just a little tricky. Otherwise layers seems to be your only option

If I understand you right (I am no C1 expert), it sounds similar in scope to Lightroom's tools for colour manipulation, and I tried this, but had problems with other regions of the image changing colours too. I guess I need CS4 or something like Viveza.

 

[Dale Allyn]

Carsten, Photoshop CS2 or CS3 can do this as well. No need to upgrade, if that's what you're implying in your post.

 

[carstenw]

Corlan, thanks for the alternative selection approach. I will try both and see which feels more natural to me, or more accurate.

I am not at all against adding more tools to my toolbox, and will definitely look at Viveza, but on the other hand I am only doing this for my own satisfaction, and I don't feel any need to skip any steps or cut any corners, so I will start with the tool that I have, and once I understand the workflow, I might add Viveza and other tools, like a portrait plugin, to speed things up. I have the Nik webpage open already...

But first I want to understand the traditional approach

Dale, CS4 is the first Photoshop I have bought I ordered it from Canada due to the criminal pricing policy of Adobe in Europe ($600US = €1100...).

 

[carstenw]

However, there are situations where it skews other prominent colors in the image too far one direction or the other. Here is where you need to make localized color edits, which may have been your real question above --- and there are several ways to skin this cat. First one is in the raw processor. C1 has the color editor which is a very powerful individual color editor. Not sure what LR has now, but I suspect they have hue sliders, so you can probably make at least coarse adjustments to bring the colors other than the sky you just matched closer to your liking WITHOUT altering the sky.

That is exactly what I wanted to do. The global changes caused local changes too great to accept. I don't want to match the shades of the sky exactly, but I want to get them closer together. At the moment some are a little purple, others a little magenta and so on, and they don't look like they were taken on the same day. There is an object in the foreground which is typically, but not always, in the shade, whose accurate colour is even more important, so I do need to do local changes at some point.

I think I didn't understand your description with the droppers and +/-, but I will give it a shot before asking more questions.

Thanks, Jack!

 

[David K]

Carsten, for the most part Viveza is just a shortcut to the layers and masks available in CS4. I use it because it saves time but I'd encourage you to follow Dale's excellent post above and get the hang of it in CS4. Also, Jack really knows his stuff in this area so if you're using Capture One I'd try out his suggestion.

 

[Dale Allyn]

An error in my post above is regarding selecting the brush tool. I realized the error after I shutdown last night and forgot to address it this a.m.

You don't use "command+B" to activate the Brush. You simply type "B". Or you can click on the brush icon on the tools palette, of course. (Hint: Brush is shared with the pencil and color replacement brush, so confirm that the paint brush is active.)

Jack's point of the +/- dropper was that if you are opting to select the color range while in the Hue/Saturation dialogue (with the eyedropper), and if you want more selection (i.e. wider selection) of similar colors (or less selection), then you can use the +/- droppers to do this. You may not need to be this specific, depending on the nature of your needed adjustments. Typically it will take a bit of trial and error.

Jack surely knows this stuff better than I. My process is always rather conservative (and elementary). Jack has a lot more experience with these tools.

 

[Jack]

Again, definitely more than one way to skin this cat and using the magic wand or the lasso or the select color range all work perfectly well too. The issue is more the mask generated -- the wand and color range tools will select all the colors in the image that color along with a total selection based on tolerance, so the selection is a bit more technical and you'll need to edit a more complicated mask to affect only the parts of the image you want it to affect. On the upside, you can edit the selection prior to the mask generation by hitting the "Refine Edge" button on the tool bar, but the nuances of using that are tough to explain in a post like this.

By using the Hue/Sat adjustment layer directly on an image, you still need to mask out the areas containing that color you don't want affected, but here you can simply paint out those areas on the included blank mask with a black, feathered brush, and easily undo or redo by painting with white or black as needed. Either way you have to edit a mask, but I find for most folks just starting out this is a simpler, more intuitive mask editing method to learn by oneself than above, and IMO makes learning to work with masks a bit easier in general.

We teach both methods on our workshops, so no right or wrong here

 

[Dale Allyn]

snip... Again, the Color Range function - Lasso tool should do the trick quite smoothly in your case. With super fast learning curve

I missed this comment and agree that it can be great as well. On the background copy, one can then select the area to change (the sky) by using the Lasso, or Select... color range, etc., and then make the adjustments as described. This will confine the Hue/saturation (or whatever) to just the selected area. This would likely be my approach too, as it would require less masking. It's good of Corlan to get that across. Some these steps become automatic, and therefore skipped in such a description.

Showing this stuff is a lot easier than posting it in forum snippets.

Edit: Jack posted while I was typing, so sorry to be adding the same type of info (again).