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View Full Version : What does iPhoto's "Enhance" button actually do?




Doctor Q
Jan 26, 2006, 03:18 PM
The "Enhance" feature of iPhoto does a good job making color adjustments to most photographs. I find I can use it most of the time for home snapshots, although I often followup with minor tweaks. I'm puzzled why Photoshop's Auto Levels and Auto Color features don't seem to do as good a job as iPhoto's Enhance button.

Is there a writeup explaining how the Enhance button does its magic? The articles in the Apple Knowledge Base only give vague descriptions like "instantly brightens the photo or adjusts its contrast levels based on preset criteria."

I'm a perpetual "advanced beginner" in Photoshop and I'm starting to use Photoshop as my editor application from within iPhoto. I'd like to know the steps to use in Photoshop to accomplish something similar, i.e., to make the initial adjustments to a newly imported photo without much thinking or experimentation. (I'll save those for the more important photos.) My goal is to be able to do this at least as well as iPhoto does.



Doctor Q
Jan 26, 2006, 07:49 PM
Judging from the many views of this thread, I may not be the only one who's curious about how Enhance works.

I've been relying on tuorials like this one (http://www.designer-info.com/Writing/image_enhancement.htm) for tips on using Photoshop for quick (and not so quick) image correction.

But my Google searches have not revealed anything about Enhance's methods. I didn't find any patents on it either.

JDOG_
Jan 26, 2006, 08:28 PM
From my limited photoshop experience, the enhance button in iPhoto seems to sharpen things up a bit, up the color saturation and level things out a bit if there is a lot of dark or a lot of light (it compensates either way). That's what it seems to do for most of my shots...I would love a pro's explanation though.

It's an easy fix for most shots, but I find it sometimes overdoes what can be accomplished with just a little tweaking. :rolleyes:
I've seen some wierd things happen with the enhance button though, many super dark shots suddenly get a blue hue.

ibilly
Jan 26, 2006, 08:57 PM
I'm prettysure that it color-corrects as well, though it seems to be much more active than PS levels' snap to neutral midpoint' (in the options window inside the levelss window). The exact action it takes, and how it finds the direction it wants to shift in, I don't know.

Heb1228
Jan 26, 2006, 09:04 PM
I think iPhoto just does a simple auto-levels, auto-white balance, and maybe some contrast/brightness adjustments. The difference in color seems to be more from the level adjustment than from a true saturation adjustment IMO.

My guess as far as why it seems to work better than Photoshop's auto adjustments: I bet iPhoto is optimized to make changes that are generally beneficial to consumer-level digital cameras whereas Photoshop's controls try to make adjustments that would apply to a wider array of image files. Just a guess, makes sense to me.

ibilly
Jan 26, 2006, 09:37 PM
Considering that it all has to be algorithm based, my guess would be that Apple made numerous subtle changes to the mathematically correct model (well, one of them... I know that PS (not PS Elements) gives you the option of 3) to make it look 'nicer' and have a bit more pop. I would also not assume that it's only one levels adjustment, given the effects of the order in which you do certain things. I couls ramble speculatively, but that's no fun to read :rolleyes:

Doctor Q
Jan 26, 2006, 09:48 PM
I couls ramble speculatively, but that's no fun to read :rolleyes:Speculation is fine with me. After all, it's a rumors site!

ibilly
Jan 26, 2006, 10:02 PM
well, if you're encouraging me to ramble...
lol

I was going to guess the order, but I failed. I couldn't decide which was better in which order. So many things in Photoshop that you could do to adjust the dark/light and color intensity, saturation, and hue. Anyways, it's not especially constuctive.

Chip NoVaMac
Jan 26, 2006, 10:08 PM
I think it is a case of the market that these programs are trying to serve.

iPhoto and the likes of the Kodak Digital Kiosk are aimed at the mass market. I seem to remember reading an industry report that said that "over sharpened and highly saturated images" sold to these customers. That is why labs like Ritz Camera a few years back did so well, their digital labs did this same thing. The current Adobe programs are aimed at photographers that want more control in their final images.

cr2sh
Jan 26, 2006, 11:10 PM
From Apple:

Enhance: Instantly brightens the photo or adjusts its contrast levels based on preset criteria.

Another random quote:

Most film photo processors manipulate pictures slightly when printing because they've learned that most customers prefer good-looking photos to accurate reproductions of the original. So they may bump up the brightness or increase the saturation of colors in an attempt to produce a more pleasing photo. That's exactly what iPhoto's Enhance button tries to do, but just as with the photo processors, it sometimes screws up. From what I can tell, it adjusts brightness and contrast, sometimes for just parts of the photo, and it can improve colors, such as by warming up skin tones or changing blue-tinted snow to white. It may be doing more, but Apple hasn't said exactly what.

So I guess only Apple knows what filters they're applying... and in what sequence.

Good question!

Counterfit
Jan 27, 2006, 02:17 AM
It is indeed very good at fixing blue snow.

Yellow snow on the other hand... :rolleyes:

TheMonarch
Jan 27, 2006, 02:39 AM
I don't know how iphoto handles color, but based on my experience with both iPhoto and Google's Picassa (Which both have an "enhance" button) is that the program decides how to level the colors based on the brightest/darkest part of the picture.

I'm not very good at explaining... Lets see...

Say your friend takes a picture of you in front of a white wall, and your picture came out underexposed. Instead of being white, the wall came out a muddy greyish white... When you press enhance, iphoto looks a the whitest and darkest points in that picture, and it notices that the whitest part of the picture is the wall... So then it will pull onto the exposure until the wall is white, but still maintaining the darks, dark (Hair, etc)

:confused:

*Hmm... I really do suck at explaining, maybe I shouldn't have said anything, it might confuse more than it helps*

Clix Pix
Jan 28, 2006, 06:24 PM
If you're in a hurry and just want to run a quick-and-dirty on a image or a few images in iPhoto, fine, but if you really are concerned about producing a image which is accurate in all ways vis-a-vis color balance, exposure, sharpness, whatever, then probably you're better off doing things the slower, more painstaking way....

I think that for the "pop" that many people expect when they view their prints, then iPhoto will do very nicely. As Chip says, the targeted market is not going to be professional photographers, it's going to be John and Jane Doe with their little P&S camera who manage to get their images into iPhoto and who want and expect their results to look the way Ritz Camera or some other outfit can produce them, with lots of color saturation and "pop..."

Doctor Q
Jan 28, 2006, 06:38 PM
I think that for the "pop" that many people expect when they view their prints, then iPhoto will do very nicely. As Chip says, the targeted market is not going to be professional photographers, it's going to be John and Jane Doe with their little P&S camera who manage to get their images into iPhoto and who want and expect their results to look the way Ritz Camera or some other outfit can produce them, with lots of color saturation and "pop..."The replies here have identified my problem and I'm grateful to understand it.

I'm unprofessional enough to like the iPhoto pizzazz, but too much of a perfectionist to settle for that when I have time to tinker. Anybody with real talent will find exceptions to any prescribed set of touchup steps, but I'm finding that using Photoshop to adjust levels, then curves, and then (giving in to my baser instincts) upping the saturation a few percentage points gives me results I like.

Enhancing in iPhoto is impressive in any case. As with the way Exposť moves, sizes, and spaces windows when you press F9, Apple has selected an algorithm that makes excellent guesses. Do you think there's code in there named "FigureOutIfThereIsSnowInThisPhoto"?

GrannySmith_G5
Jan 28, 2006, 09:30 PM
Enhance in iPhoto seems to give photos auto-levels and auto-contrast adjustments as well as a saturation or "vivid color" boost for ideal brightness when printed on an inkjet printer with glossy paper.

When in photoshop a good place to start(with an image that is fairly decently shot already) is with a levels adjustment layer. When you click on option you can preview three algorithms(auto levels, auto contrast, and auto color) and then refine from there.