Introduction

These are the full technical image guidelines provider by our TV channel partners.  Microsite owners can now upload their own images which so these full technical guidelines are for information only.

Interactive TV Colour Requirements

Application authors are advised to use PAL safe colours exclusively in their interactive TV applications.

(You could also use the NTSC filter in Photoshop 7 and above)

Colours whose R,G or B values are in the range 0-16 or 236-256 should not be used. Application developers should set the saturation levels of their images to range between 16 and 236 for the R,G and B channels using the Levels interface in Photoshop.

Some colours with in these ranges will still flicker on the TV screen.

Application authors are advised not to use the following colour combinations, as they can cause screen flicker and "barber pole" effects:

• Black and White
• Red and Blue
• Yellow and Purple
• Red and Green
• Blue and Yellow
• Green and Blue

JPEG Image creation - Sky Active Platform

Please find below instructions to create logos and content images for your local authority DiTV microsite. Note we are specifying to the Sky standard which is the worst case scenario, and as such allows cross-platform compatibility.

The Sky platform currently cannot render any JPEGs with a version number higher than 1.1. This information is held the header of the image; invisible to the eye the header allows applications to identify what type of image it is.

The problems have been occurring when newer versions of the JPEG format (ie. Version 1.2) have been resaved in as a lower version (1.1). Some of the original header information remains in the image. There are also some issues with image creation and compression settings, which must be implemented correctly.

To avoid this in the future there are several steps we can take:

1. Ensure colours used are 'websafe' or if possible NTSC safe.
2. Ensure the logo or image appears on the correct background size (ie the standard template).
3. All JPEGs dimensions must be divisible by 16 pixels and sit on a 16 pixel grid.
4. JPEGs must be saved out in a Non-progressive Format
5. JPEGs must be saved in version 1.1 (see checking version below)

Creating your JPEG

The following are some simple steps, which will enable you to create effective JPEGs for logos and content images for the Sky Active Platform.

1. The size for a logo is 272 x 96 pixels (w x h), for a content image 240 x 240 pixels
2. For logos - leave a 10 pixel minimum gutter from the edge of the area to allow the logo to breathe.
3. If colours are highly vivid and saturated, reduce the overall saturation of the image. E.g pure black or white in an image would require slight de-saturating.
4. Keep file size to a maximum of 10Kb (logos) and 300Kb (images), to allow for quicker loading. The greater the compression the better, though high degradation of the image quality should be avoided.
5. Get original logo artwork, this artwork should only have been saved once after creation. This artwork could be in the following formats: .ai (Adobe Illustrator), .psd (Adobe Photoshop), .tiff, .eps, .png (Macromedia Fireworks). If the format you have isn't listed here don't worry, just ensure it hasn't been saved several times before you use it.
6. Place artwork on to the 'Background' Template ensuring the background white has the following RGB value: 235:235:235.
7. Save artwork as a .bmp. If you have created the logo or image in Adobe Photoshop ensure that all the layers have been flattened before you save as this will reduce file size.
8. Use Microsoft Paint (Start/All programs/Accessories) to save your logo or image file as a JPEG. 
9. JPEG created.
10. Your image can be checked for Sky compatibility using the DigiTV jpeg checker.