Okay, so the headline of this post isn’t one of my best, but it is a real problem many iPhone 4 users don’t notice until it’s pointed out.

GreenSpot Fix removes the blue-green tint in the center of a photo when the picture is taken under fluorescent lights on an iPhone 4. I’ve experienced interference issues from some types of lighting in the past. For instance, I found that transformers in some halogen lighting can cause interference and static bands on the iPhone camera. While I don’t know the exact science behind GreenSpot Fix, I suspect that the tints from fluorescent lighting are caused by the frequency of the fluorescent bulb not always meshing with the scan frequency of the CCD of the iPhone 4′s camera. If you shoot photos on your 4 under fluorescent lights, you can easily see the discoloration.

There are several apps available which remove the blue-green tint from images. GreenSpot Fix does as good as or better than most. The app is easy to use. Simply load an image and select one of the nine presets. The app quickly and automatically balances out the color, reducing or removing the blue-green and red tints. You can maximize the preview and adjust the intensity of the effect, but I found that in most cases, one of the presets worked great for me as is.

The app also features “Black Filtering” which is supposed to help maintain the richness of dark colors after processing. I’ve never had this problem with other tint scrubbers, but it seems to work fine in this app. I guess I’m glad it’s there.

The app saves images at their original resolution. There’s no reduction in size or loss of pixels.

There’s a great online help to guide you through some of the settings. The developer is from Korea and some of the text is in Korean, but using help or intuition, it’s very easy to figure out the English usage.

The price is great — free! There’s a small iAd at the bottom of the splash screen — that’s all. The work screen is ad-free. This is an excellent app and an essential utility for iPhone 4 owners.

From the developer’s App Store description:

Annoyed to find a big green spot in the middle of your picture frame when you take a picture with your iPhone 4? GreenSpot Fix is a free application which removes the GreenSpot (green circular hues) that may occur when you take picture under the fluorescent lighting with your iPhone 4.

GreenSpot Fix has its own unique and innovative function called Black Filtering, which removes the GreenSpot completely whilst keeping your black color looking still vivid. Black Filtering technique distinguishes black color and prevents it from being removed during the fix procedure. Using this technique, you can prevent black from changing to reddish black, thus eliminating just the green spot!

GreenSpot Fix works on any iPhone, iPad or iPod Touch running iOS 4.1 or newer. It’s a free app.

GreenSpot Fix - OTIV Lab