In this section we will deal with working in Photoshop with your
wide gamut aRGB monitor and will consider how best to save images
to the web in such a manner that anyone else viewing them stands
the best possible chance of seeing them presented correctly. You
may have experienced strange colour shift behaviour in "Save
for web" and wonder what's going on and we will address that
Before I get to Photoshop, just a few words about camera settings.
If you shoot RAW as I repeatedly recommend throughout my tutorials,
then it doesn't matter whether you define the aRGB colour space
at this point or not. RAW does not assign a colour space, you
can choose either sRGB or aRGB it doesn't matter. Only when the
RAW image is converted is colour management information embeded.
This is not the case if you use jpeg. The camera will assign the
profile that you set in camera.
Working in Photoshop - settings for aRGB color space
1.0 Color Settings
Photoshop and Lightroom are examples of colour-aware editing software.
However, you need to tell them some basic information at the start.
For example, in Photoshop, go into Edit >Color settings and
set it up as per my own settings below and you will be fine. I
have the box marked Profile mismatches when opening files box
ticked as this is very useful I find.
2.0 Adobe Camera RAW (ACR) settings
On opening a RAW image in ACR you will see at the
bottom of the screen where I have circled below some small but
Click on this text and another box opens :
The top white box enables you to select Adobe RGB (1998) to be
selected from the drop-down list and you should set the Depth
to 16 bit. This is best for doing image editing with minimal damage.
This setting temporarily doubles the filesize so you will need
to remember to convert back to 8 bit in Photoshop later or you
will be occupying double the storage space on your computer !
To do this click on Image > mode > 8 bits per channel.
I set resolution to 300ppi as this is the industry standard resolution
I don't tick the output sharpening box as I will sharpen myself
later in Photoshop according to what I am going to do with the
image e.g print, output for web etc. The degree os sharpening required varies according to the image size so it is best to do this as the lsat satge in your workflow.
Click OK and you are set. You will convert images into aRGB upon saving or opening.
3.0 Opening images in PS - Profile mismatch warnings
If you only have aRGB images and you have Photoshop and ACR set
up as above, then aRGB images will simply open correctly on your
However if, like me, you have a mixture of aRGB and sRGB images, when you open an image that is in a different
colour space to the current working one, then as long as you have ticked the
Profile Mismatches box in Photoshop > Edit > Color Settings,
you will get a warning that the document does not match the working
colour space. It looks like this:
So, how do we decide what to do ? In the example above, I attempted
to open an image that had an sRGB profile embeded, into the Photoshop
aRGB colourspace. Photoshop therefore brought up a warning. If
you are intending to keep the image as sRGB and perhaps are intending
to resize it and upload it to the internet you need to select
"Use the embeded profile (instead of the working space) "
then click OK. The image will then open in Photoshop correctly
as Photoshop has retained the sRGB tag and knows how to handle
it to appear correctly.
I don't usually use the "convert the documents colours to
the working space" when opening an sRGB image as the image will be upsampled
to invent the missing data as it is going from a small to a large
colour space. If going the other way from aRGB to sRGB it is less
harmful as image data is simply being discarded rather than invented.
I haven't yet found a use for the "Discard embeded profile
(Do not color manage)" option.
Opening untagged images.
Finally, the last option that I need to
cover is bringing an untagged image e.g. from the web into Photoshop.
I first noticed this issue when I downloaded one of my own images
from the internet and saved it onto my computer. When I opened
it in Photoshop I did not get a warning and I noticed that it
was an untagged image. How did I realise this ?
Well for one, the image was oversaturated
and secondly there is a small information box on the bottom left
of the Photoshop toolbar that can be changed to profile via clicking
the arrow beside it which brings up a drop down list of options.
So this is an easily overlooked situation
on some images as there will be no obvious warning as before.
So how do we deal with such images ?
If you click Edit > Assign profile
or convert to profile you have a range of options open to you.
As the names suggest, if you assign a profile it will only be
temporary and the document is not actually changed, however if
you convert to Profile you change the image profile permanently.
You can of course undo this at any time but it will be destructive.
Just choose your desired course of action as once tagged, all
options will look correct in Photoshop as it knows what to do
In part 4, I will cover "Save for web" issues.