How to turn off all colour management?

What happens when you generate an ICC profile from your "high end" calibration, and then use that profile - as your RGB working space. That would be the easiest way to effectively send RGB directly to the screen without any outside intervention.

Andrew Rodney (wrote here previously): since PS5, the architecture has been such that Photoshop always makes some assumption about the numbers for previewing and conversions using ICC profiles. You can try and turn it off but it's always looking for a display profile for previews along with an embedded profile in a document. Even if you strip out the profile, Photoshop is still going to make an (assumption) about the numbers, again based on some ICC profile.

In any case, I would pay very close attention to what Chris Cox added until you completely understand what he is saying.

But I am curious, how you are running Photoshop with no monitor profile selected in Photoshop?

What profile is listed under "Monitor RGB" in Photoshop> Color Settings> Working Spaces> RGB? (click on the RGB and you should see the drop menu as pictured here):

Whatever Photoshop is using for Monitor RGB is the profile Photoshop is Applying/Assigning/Assuming to your file (for all practical purposes) when you don't color manage your file.

Monitor RGB profile there also is the profile Photoshop displays through (ie, Source Profile to Monitor Profile).

This is the same profile Photoshop Applies/Assumes/Assigns when you View> Proof Setup: Monitor RGB

Well, it would probably help if you could explain a little more in detail what you are doing and why you want to turn CM off.  It would also help if you would verify what version of PS you are using.

One of the challenges you are going to face is that it really isn't possible to turn off color management completely in recent versions of Photoshop.  There are always SOME assumptions being made.  Here are some comments from Andrew Rodney on the issue:

http://www.gballard.net/psd/psdcm4678cs.html

Now if what you are trying to do is produce images that will look OK for the largest audience (that means including people who are using non-color-managed applications and browsers), here is what I would recommend:

- Use sRGB as your RGB working space in Photoshop.

- Put "Convert to Working RGB" in the RGB Color Management Policy.

-  When you save the image, you can save with or without an embedded profile.  It's your choice.  Most common applications and browsers will assume sRGB or something reasonably close if there is no embedded profile.  I normally save WITH embedded profiles since it makes the colospace clear to everyone, including myself, and it also helps Safari users a little.

Now the other component is your monitor profile, the thing that adjusts the viewing on YOUR monitor so that it produces results close to a standard.  I don't know if in your case you are using a custom monitor profile (produced from a calibrator/profiler like Huey, Spyder, Eye One, etc.) or perhaps a display profile from the manufacturer (Dell2408WFP, for example) or maybe a standard colorspace profile like sRGB.  It might be helpful if you would tell us which and also mention what operating system (Windows 7, Apple Snow Leopard, etc.).

Anyway, Photoshop will be using that monitor profile automatically (its use is different from the RGB working space in Color Settings).  If it is standard colorspace like sRGB or a manufacturer's display profile, it is likely that Photoshop will match the image in a non-color-managed application or come relatively close.  If you are using a custom monitor profile, then you may see significant differences.  If you don't like those differences you can:

- Stop using your custom monitor profile and try a manufacturer's o sRGB profile for your monitor profile (changed in your operating system, not PS).

- Use View>Proof Setup>Monitor RGB (or Internet Standard, I always forget which) to view a temporary version that is without the monitor profile.

- Start using color-managed applications like Firefox or Safari.

Note that using a custom monitor profile is NOT a bad thing.  What it allows you to do is make corrections for deviations from the standard that your monitor may need.  When creating an image in the common sRGB colorspace, for example, using a custom monitor profile whill help you produce an image as correctly as possible to that sRGB standard.

Also if it wasn't clear already, there is no such thing as "no colorspace".  The closest thing to a "no colorspace"/"no profile"/"no complications" standard today is sRGB.  There is a point beyond which you can't worry about how everyone else is going to see your images.  You have no control over how they adjust their monitors, what applications they use, and whether or not they know the first thing about color management.  All you can do is produce your images as close as possible to an industry standard (my recommendation is sRGB for normal web use) and meet them half way.

Hope that helps.