“What is Colors AlTaglio?” Colors AlTaglio is the iOS 9 Photos extension for editing the palette of colors of your photos using gamut masks. “What is Gamut Masking ?” Gamut Masking is a painting technique that allows the creation of harmonic color palettes by selecting a region of the color wheel with a polygon, usually a triangle or rectangle, this polygon deﬁnes the range of colors available for a painting. It’s a technique that James Gurney popularized with his book Color And Light. Colors AlTaglio replicates this artist’s technique as a photo ﬁlter for the ﬁrst time ever. In order to do so, it works with the CIELUV derived color space HUSL, this allows it to modify the hue and saturation of any pixel without changing its perceptual lightness.
Usage: To launch the AlTaglio extension ﬁrst you need to open the Photos app, view the photo that you want to edit and tap on Edit.
Then tap the More button with the three dots and select AlTaglio from the list of extensions.
The ﬁrst time you will have to enable it by tapping More once again. The companion app that will appear on your iPhone screen also contains a usage guide. The extension screen has these components.
Preview: This is where you see the changes you’re making to the image, tapping on it will display the photo full screen and then you’ll be able to zoom in. While on the zoom view you can touch and hold to see the original image or tap again to return to the main screen.
Color Wheel and Gamut Mask: Below the preview is the mask editing area, you can move the color points to modify the mask to your taste. You can also pinch to enlarge or reduce the mask or rotate it with two ﬁngers. In the center of the mask you’ll see a cross point, this indicates what color will be used as the neutral color, it’s very similar to the white balance. By default it will move around as you transform the mask, being always in its centroid, but you can move it to anywhere you like inside the mask. After you move the neutral color it will no longer move when you edit the mask and that can limit the range of movement of the color points. To reset it to the default position again just tap twice on the mask.
Masks: At the bottom of the screen there are a few controls, the ﬁrst one is a collection of preset masks that you can use as a starting point for your editing. Among the masks, there’s an empty mask that you can use if you only want to rotate the hues.
Amount: This setting lets you specify the intensity of the gamut masking ﬁlter, at its maximum value all the colors will be inside the mask.
Resaturation: This setting tries to compensate the fact that a gamut mask eﬀectively reduces the saturation of an image by limiting its palette. Larger values will make the colors closer to the mask vertices to be even closer to them, so they’re relatively more saturated, but large values can also produce unwanted artifacts in gradients.
Rotation: This setting rotates the color wheel changing all the colors at once for funky eﬀects or, if its a subtle change, it can function in a similar way as a temperature change. To quickly remove any rotation double tap on the slider. This setting is independent from Amount and Resaturation.
Colors AlTaglio is available on the App Store for just $1.99/£1.49/€1,99. Colors AlTaglio is designed for iPhone and iPod touch. Colors AlTaglio requires iOS 9.1 or newer and a 64-bit processor. If you have any questions about this blog post, please leave comments Have a great day and see you soon !!!