App: Color Contrast
Developer: Accessible Resources Ltd
Genres: Graphics & Design, Photo & Video

Color Contrast is a tool to measure the contrast between two colors in a screenshot or mobile website, helping ensure your app meets the internationally recognized recommendations in the Web Content Accessibility Guidelines (WCAG), for both versions 2.1 and 3.0 (Silver)

Color Contrast has the following features:
+ Verify that the color contrast between two colors in an app, website or photo is sufficient to pass WCAG 2.1 accessibility guidelines / Section 508.
+ View suggested colors
+ Generate a report that can be shared using SMS, Email or Notes.
+ Verify color contrast directly from Safari and Photos app.   
+ Audit web pages for compliance using AXE.

To use Color Contrast

1. Load an image or website by tapping the icon in the top right corner. The image can be an existing image from the Photo Library or a new picture taken with the camera. Enter a URL to load a mobile website.
2. Move each color picker in turn to select two colors. 
You can also pan around the image by swiping left/right/up/down or pinch to zoom in/out.
3. The Color Contrast results will be displayed at the bottom of the screen.
4. Tap the 'Share' icon to create a report that can be emailed, added to notes, copied or saved to your Photo Library.

About WCAG 2.1

WCAG 2.1 accessibility guidelines have three levels of compliance, A, AA and AAA. When considering large text (i.e. text which is above 18pt or larger), the minimum AA color contrast ratio is 3:1 and for AAA the ratio is 4.5:1. For normal text, the AA color contrast ratio is 4.5:1 and for AAA the color contrast ratio is 7:1.

For more information about WCAG 2.1, see https://www.w3.org/TR/WCAG21/

* WCAG 3.0 (Silver) *
The W3C Accessibility Guidelines 3.0 (Silver) reference an experimental color algorithm known as S-LUV Advanced Perceptual Contrast (SAPA) or Advanced Perceptual Contrast Algorithm (APCA).  This algorithm can be enabled within the app via left-hand menu. To re-iterate, this algorithm is experimental and is likely to change in future.

For more information on SAPC-APCA, visit https://github.com/Myndex/SAPC-APCA/  

Copy colors to clipboard

With Color Contrast you can also copy the current color to the clipboard in the follow formats:
- HTML Hex (e.g. #EEFFEE)
- UIColor from RGBA (e.g. UIColor(red:0, green:0, blue:0, alpha:0) )
- UIColor from HSB (e.g UIColor(hue:0, saturation:0, brightness:0, alpha:0))

We are continually improving Color Contrast, if you have any questions or feedback, please contact info@accessibleresources.com

Release notes:
Improved UI for Suggested colors