Welcome to the Life after Photoshop photo-editing A-Z. It’s very easy to use – just click a heading to expand a definition of that term. There are links to specific programs and many of the entries link to a tag which will show related articles. I hope you find it useful.
British vs American spellings
This A-Z uses British rather than American spellings, e.g. ‘colour’ rather than ‘color’. Apologies if this is confusing. This link may prove helpful.
0-9
- 4K UHDThis is the 4K video format used by most cameras. It's not strictly 4K as the horizontal resolution is 3,840 pixels not 4,000 or above, but it's close enough for most purposes, especially as it preserves the same 16:9 ratio used by the Full HD and Standard HD formats and, indeed, most laptop and computer screens and TVs.
- 4K videoThe latest consumer video standard, with a horizontal resolution of 4,000 pixels or thereabouts. 4K video is appearing on an increasing number of cameras and even smartphones, and 4K TVs are gaining in popularity. Strictly speaking, the dimensions for 4K video are 4.096 x 2,160 pixels and the aspect ratio is slightly wider than the 16:9 standard for HD video. In fact, what most makers and users are referring to is UHD video at 3,840 x 2,160 pixels, which does have a true 16:9 aspect ratio.
- 8-bit imageThese are photos which use 8 bits of data for each of the red, green and blue colour channels. This is enough to give over 16 million colours – more than enough for photographic images. The JPEG photos taken by digital cameras are 8-bit images.
- 1:1 ratioThe 1:1 aspect ratio means an image that has the same width and height, i.e. it's square. So why not say 'square'? It's because many programs have crop tools that quote specific aspect ratios like 16:9, 3:2 or 4:3, so for the sake of technical consistency square images are referred to as 1:1.
- 14-bit RAWThe ‘bit depth’ of RAW files is a factor in the picture quality they can produce, so this is a selling point for advanced digital cameras. Some cheaper models can only shoot 12-bit RAW files, but while this sounds like a small difference, the extra bit depth potentially offers 4x the image data so 14-bit RAW files are a worthwhile benefit, especially if you want to process photos heavily later.
- 16-bit imageThese are photos with 16 bits of data for each of the red, green and blue colour channels. These aren’t created directly by the camera, but you can generate 16-bit images from RAW files and they withstand heavy image manipulation better than regular 8-bit images. The file sizes are much larger, though, which puts more pressure on your computer’s storage capacity and slows down file transfer speeds, and not all software can edit 16-bit images.
- 3:2 ratioDifferent camera types have different aspect ratios. Full frame sensors, APS-C sensors and the smaller 1-inch sensors in many high-end compact cameras have the same 3:2 ratio as old 35mm film negatives. This gives a pleasing semi-wide aspect ratio for horizontal images, though doesn't work quite so well visually for vertical shots.
- 4:3 ratioThis is an aspect ratio used by many medium format cameras, Micro Four Thirds cameras and compact cameras with small 1/2.3-inch sensors (like bridge cameras or point and shoot compacts). Visually, 4:3 images look slightly taller or less wide (however you want to look at it) with horizontal images, but the 4:3 ratio is quite pleasing for pictures taken vertically.
- 16:9This is the aspect ratio of full HD and 4K UHD video and it’s been widely adopted as the aspect ratio for domestic TVs and computer monitors. The 16:9 ratio means that the picture is 16 units wide by 9 units high. These units can be anything from pixels to centimetres to inches, but the point is that the ratio between them always remains the same at 16 wide to 9 high.