Understanding selections, masks, and alpha channels

- At this point it's a good idea…to bring in the first wagon.…Of course you find all the wagons in the project files,…but we start with wagon number one.…The wagon is right here.…It looks like that, and as you can see…I produced already a layer mask…just by loading the selection.…And now I shift click the layer mask…and you see what it does.…OK, if we want to bring this over to this train…we take a look at the wagon, at the train,…at the wagon, at the train and we notice…the color is not the same (laughs).…

Yes, that a lot of times happens even if you take…the pictures of the same train on the same platform.…The weather might have changed in the last two minutes,…the sunshine might have changed…and we see that the color is different.…So, first thing I would like to do is to match the color.…And I do this by just arranging both images…right next to each other - we go to Arrange, 2 Up Vertical…and now we see the train and the wagon.…

Maybe a little bit closer, OK.…This is the one I would like to change,…and so I go to the Curves, of course I could try to change…