To make turn an image into CMYK (print) you could use 2 methods; image, mode, CMYK colour. However this is destructive which means once saved and reopened there's no way to get the original image back. This could cause problems if working for a publication that wanted an image for print but then realise it would also look good on their website.
To get around this we use proof colours, this enables us to view the colours it'll print out. We can tell from using this the photo will print out considerably duller.
To find out what colours will print out well we can use the gamut warning. Gamut = colour range; therefore if it's out of gamut, the colour is out of range.
Below we have used gamut warning and from this we can tell that the photo is vastly out of the CMYK colour range because of the grey parts.
If we change the hue (the colour of the light) to red the grey parts vanish, meaning the photo is now in gamut range and is a much clearer image.
We always have to proof to show as well.
Making sections of an image clearer
To make certain sections of an image clearer we can make the photo lighter by using levels. By altering the white levels we can make the image a lot lighter to reveal the mosaics on the ceiling.
However the glass on the roof has become far to light and we have lost all detail, by masking the sections of glass we can affect what sections of the photo are affected by the change in levels. To mask sections off we simply block different parts of the glass on the levels layer with the black paintbrush tool.
By masking the glass sections we end up with the original glass coming from the original layer.
There is another way to lighten specific parts of a photo (mask). By using the quick selection tool we can select only the statue because it is so dark in contrast to the sky.
Once the image is selected we can then change the levels in a non-destructive way same as the previous technique.
However changing the levels has also changed the levels of the clouds in the tiny gaps in the statue that show clouds. To fix this simply magic wand the white bits, edit, fill, and fill them black which simply masks them off.
We can also alter the clouds by selecting the clouds using the quick selection tool, selecting hue/saturation and playing around with colour.
Go to file, automate and photo merge. It should then bring up a window similar to the one below, from here upload the set of images you wish to align and merge.
Something similar to the image below should be created and all that is left to do is to crop the image to a rectangular shape to neaten the edges.
