Just before the Christmas break, I decided to spend some time over the holidays comparing Adobe’s Photoshop Lightroom, Apple’s Aperture and Phase One’s Capture One raw developer/digital asset management products. By way of background I’ve been a Lightroom user since the earlier betas, and really like Lightroom’s workflow management. But I’ve never been happy with Lightroom’s color rendition, but have also not had the time to really dig into why I wasn’t getting what I wanted. But by just before Christmas, I was sufficiently frustrated that, despite what I like about Lightroom, I was in “there’s got to be a better way than this” mode – ready for change.
Now one person’s great color rendition is another person’s nightmare, so there isn’t any point in trying to just play with the sliders till something nice comes out – at least not for me. Also, on some products there eighteen sliders, all of which interact. I accept that there may be people out there that can look at an image, move a few sliders, and get what they want, but that isn’t me. So what I’ve chosen to do is to look at color rendition in a more “scientific” way; and ask three questions:
- How close is the default rendition of each product to a 24-patch GretagMacBeth color checker?
- How easy is it, using each product to calibrate the rendition to as exactly as possible match the theoretical values of the GretagMacBeth test chart, as printed on the instruction sheet that comes with the chart?
- How usable is the calibration that I’ve created – is it easy to transfer to other images, how sensitive is it to changes in exposure settings, etc.
At least, while calibrating to to a GretagMacBeth chart doesn't mean I'll have "good" color, at least it's a consistent starting point. And yes, accepted that questions 1 and 2 are fairly simple and objective questions, but that question 3 starts to get more subjective.
As perhaps I might have expected this turned out to be a far more complex process than I’d thought, and eventually pulled me into comparing the three products quite a bit more broadly, for example, as regards the performance of their Bayer interpolation engines.
For the record, the software versions used for this comparison were:
- Lightroom 1.3.1 Camera Raw 4.3.1
- Aperture 1.5.4 and 2.0
- Capture One 4.0.14154.14152 and 4.0.1.14900.14887
Now the first issue that comes up when trying to do this is a simple one - given that, for example, the skin patch on a GetagMacBeth cart has the l*a*b* color values of (65.711, 18.13, 17.81), what does that actually mean in terms of the RGB values that we should expect to get from the cursor read out in each program. A little of experimentation will show that this isn't a simple question.
Actually there are two issues with trying to calibrate imaging software - in what units is the readout, and secondly what adjustments are being applied to the image. Typically, when a raw developer loads a TIFF file, it does so without adjustment, but usually applies some kind of tone curve when loading a raw file.
The readout units for the programs that I've calibrated are:
- Lightroom: Melissa RGB - Melissa RGB is the combination of the ProPhoto primaries and the sRBG gamma curve, Also known as "bastard RGB", as it's the bastard child of ProPhoto and sRGB.
- Aperture: Wide Gamut. (Note: this was correct at the time this post was originally written. But see the comments this year below - its now Adobe RGB. However, the color rendition information is still correct)
- Capture One: Capture One uses whatever color space is set as its output space, so you can set it to any ICM profile you have. For a bunch of ICM profile you can use, see my ICM Profiles page.
The adjustments made by default are more complex - generally, each raw developer has its own tone curve, and also its own default brighness settings.
This is the graph of the ACR 3 default tone curve, as extracted from the Adobe DNG toolkit - it shows the flatting at the top and bottom of the curve, and also the default brightness setting
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq8ZZRRnwdTwGyM42x8D53FNWPdP8Gay4DTEJwD2smLi4UFcM-dHNz5ioa6fu6IyXeizeXrCHFwGDgiLfkYtDazTNL9U96p52uXzROe5KCdW-hQWIbAUrmMztpz9PHhOn7a5eeMQmWIb_w/s400/MonochromeTestChart.jpg)
What I've done to get real tone curves from the packages I'm looking at is to use the monochrome stepwedge reference image (shown above, and available in DNG format on my Reference images page) to work out what the tone curve is.
In part 2, I'll show those curves.
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