Possible solution for problems printing with ICC profiles - esp. R2400

Question

(N.B. This is long because I've decided to go in to details about the background of the problem etc.. Also note that whilst my experience is with the Epson R2400, anyone with problems printing using ICC profiles in Aperture may find this post helpful, as will be explained further down the post.)
Ok, here's the situation. I've been an Aperture user for over a year, and an R2400 owner for half a year. In that time I have done a huge amount of experimenting, but I've never managed to get Aperture to work perfectly with Epson's 'premium' R2400 ICC profiles - the ones you can download from their site which are better than the ones provided 'in the box'. This hasn't been too big a deal because, in fact, the R2400 does a rather good job just set to 'System Managed' in Aperture and 'Epson Vivid' with a gamma of 1.8 in the printer driver. Nevertheless, it really annoyed me that something that should work wasn't, which is why I've spent a lot of time trying to figure out what's going on. Having said that, I have come across a method which will give you pretty good prints out of your Epson R2400 using the premium profiles in Aperture - it's not perfect, but it's the best you're going to get if you want to use those profiles in Aperture. I understand the words 'it's not perfect' aren't what photography experts would probably want to hear, however, I have seen a few anguished posts from R2400 owners in here before, so I think some people may find it useful.
The whole reason why Aperture is hopeless at using the R2400's premium profiles is because - unusually - their default rendering intent is set to 'relative colorimetric' rather than 'perceptual'. You might say 'but that's good - it means you get more accurate colours!', and if you do, you're right... however, there's a snag. To get an image to reproduce well using Epson's premium profiles and relative colorimetric rendering, you really need to use black point compensation. This is where the trouble lies: Aperture's black point compensation is diabolical to the point of being unusable when used with relative colorimetric rendering - I feel I need to be awarded compensation every time I've ever tempted to use the setting. So because BPC in Aperture is unusable, that effectively makes the premium profiles unusable too, because Aperture always uses the default rendering intent specified in the profile.
The solution? Use perceptual rendering instead. Ok, so you can't change the rendering intent in Aperture, which makes that sound a tad difficult. However, as I said in the above paragraph, Aperture always obeys the default rendering intent specified in the profile... so you can see where we're going with this: we need to change the ICC profiles' default rendering intent from 'relative colorimetric' to 'perceptual'. I did some digging around and found one or two expensive pieces of software that could do that... but then I found that, lo and behold, the Mac OS has a command-line utility which can do the job for us, for precisely £0.00. It's called SIPS or 'Scriptable Image Processing System', and you can find out some information about it here: http://developer.apple.com/technotes/tn/tn2035.html#TNTAG58 For those who don't like reading technical jargon however, here's what you need to do to convert a profile's rendering intent. First go to terminal, then type in the following command:
sips -s renderingIntent perceptual
Do not press 'enter' yet. Instead, add a space after 'perceptual', find the ICC profile you want to modify, and click and drag it into the terminal window. You should then find that your command looks something like this:
sips -s renderingIntent perceptual /Users/yourname/folder/RandomProfile.ICC
At which point you can then press 'enter', and the command will execute, giving you an ICC profile which will now make Aperture use perceptual rendering.
There is just one further thing to be aware of after doing this: for some crazy reason, you then need to turn on BPC in Aperture for the prints to come out as good as possible. Black point compensation shouldn't make any difference when using perceptual rendering as the idea of perceptual is that it takes account of things like that anyway, however, in Aperture BPC does make a difference, so remember to turn it on to get a half decent print. In general, I find that prints made using this setup come out pretty well; they almost perfectly match prints made using the profiles with a perceptual intent in Photoshop Elements, except for the fact that Aperture blocks up the shadows a bit more than Photoshop. However, if you can live with that, you might find this is quite a workable solution.
Now, I said near the beginning of this post that all the above can apply to other printers too. Most printer profiles have 'perceptual' set as their default rendering intent, in which case everything I've just said won't be of much help. However, If you are reading this because you're having problems with ICC profiles in Aperture, but you don't use an Epson R2400, find your problematic ICC profile, double-click on it, and take a look at the window that opens: specifically, at the 'Rendering Intent' the window mentions. If it doesn't say 'Perceptual' then it may well be worth trying the steps I've outlined in this post to set it to perceptual, to see if doing so produces an improvement when using the profile in Aperture.
Finally, just one note of caution: if you decide to try out the steps I've detailed above on a paid-for custom-made profile, please back your profile up before messing with it. I haven't experienced any problems when using SIPS to change a profile's rendering intent, but I obviously can't guarantee that it won't do something weird and corrupt your expensive custom-made profile.
If you have any questions, feel free to ask, although (contrary to any impression I may give) I am not a colour-management expert; I'm just someone who doesn't give up when they have a problem that should be solvable.
Thomas
Mac Pro 2.0GHz with 30" ACD; 15" MacBook Pro 2.0GHz   Mac OS X (10.4.10)  

Answer 1

Thomas
Wow - thanks for such a comprehensive post.
I have Aperture and a 2400 so this information is exceptionally useful to me.
Again - thanks for caring and sharing
Brian