According to experts, image quality is “primarily, not the result of a photographic process in a camera, but the result of storing or transmitting the image. A typical example is a digital image that has been compressed, stored or transmitted, and then decompressed again. Unless a lossless compression method (like RAW) has been used, the resulting image is normally not identical to the original image and the deviation from the (ideal) original image is then a measure of quality.
In a typical digital camera, the resulting image quality depends on three factors; how much the image formation process of the camera deviates from the actual light passing through the lens, the quality of the image measurement process, and the coding artifacts that are introduced in the image produced by the camera, typically by the JPEG coding method.” (source: https://en.wikipedia.org/wiki/Image_quality)
Okay! I understood that perfectly!
Truth is, that’s a lot of technical gobbly geek for those of us who just like to shoot and post our images on Facebook and our websites. While, for photographers, the best way to ensure a good quality photograph is to expose and focus the image correctly, there are a few other things that can be done to ensure that you get the best quality image that you can from your camera to your computer, to your print. I use Adobe Photoshop CC to edit my images — highly recommend!
Ten Helpful Tips for Improving Your Image Quality:
1. Calibrate your monitor
The appearance of your digital images will vary according to the monitor you use, and again on the printed page. One vital operation to carry out regularly is to calibrate your monitor. This can be done with specific software packages and on-screen meters, or more easily with the Adobe gamma software, which is an integral part of Photoshop. If using a CRT, make sure that the monitor has been running for around half an hour before the calibration process, and that any ambient light is consistent with the normal working environment. Another important point is to make sure that you have a neutral gray desktop on your monitor, against which to view the images.
2. Use Adobe RGB (1998) Color Mode. This is the industry standard for most imaging professionals.
3. Don’t Over (or Under) Expose.
By definition, the histogram is a “graphical representation of the tonal values in an image.” Check, and if necessary correct, exposure using the histogram (Levels) on your camera or in your photo-editing program. The black point should be at or near 0 for most images, with the white point at or near 255. Stock agencies and many publications will expect the black/white points to be within 5% of these values, i.e. black at Level 12 or below, and white at Level 243 or above. There are exceptions of course – for example, extreme high-key or low-key shots, and misty, atmospheric images may not contain the entire tonal range from black to white.
In Levels, if most of the tonal values in the histogram are bunched up towards the left, the image is probably under-exposed. If bunched up towards the right, it’s probably over-exposed. Use the centre slider (gamma) – or for more control use Curves – to try to improve matters, but there’s a limit to how far you can go before image quality deteriorates. Raw shooters should go back to the original Raw file and make corrections there.
4. Reduce the Noise
There are various software packages available for noise reduction. While some of these packages achieve very good results, they generally work by softening the image. It’s advised to use this software sparingly to avoid introducing softness and unsightly artifacts in your images. When using any noise reduction techniques, always remember to check your results at 100%.
5. Don’t Use Image Interpolation (increasing size of image) Without Professional Software
When an image file is increased in size, software has to ‘create’ extra pixels to fill the gaps. This is called ‘interpolation’ of the image. Commercial uses require photo scans to be un-interpolated and digital camera files to be interpolated up to 24MB. If you have a camera that is capable of producing an uncompressed 8 bit, TIFF file size of over 24MB, then leave it that size. If you need to interpolate your digital camera files you must ensure that you use a professional software package, such as Abobe Photoshop.
6. Check for a color-cast
With the Eyedropper Tool set to a sample size of 5×5 pixels, place the cursor over a known neutral (black, gray or white) area. Now check the RGB values in the Info Palette – they should all be identical. If they’re not, use one of the various color balance methods to make them equal.
7. Save Sharpening Until Last
The normal process of preparing an image for repro always includes sharpening. This is best done only once and as the last step in your photo processing. If you apply sharpening to sharpening, unsightly artifacts can appear. Do not sharpen during the process of photo editing and save that change for the very last step.
8. Save Grayscale Images to RGB
If you are working with grayscale images, save them as RGB prior to submitting them to any stock agency or publication.
9. Check your images at 100%
Always carefully check the quality of your digital files at 100% before you do a final save. 100% means that one monitor screen pixel is displaying one image pixel. This is the only way to see every pixel in your image, it is important that you check all of your images at this zoom. In Photoshop, the keyboard shortcut for 100% is Ctrl+Alt+0 (PC) or Cmd+Option+0 (Mac), or double-click the zoom tool.
10. Save the image as a high-quality JPEG file (level 10 or above in Photoshop).
Make a habit of doing this for all of your images – you’ll be pleased with the results.
- Photoshop in 60 Seconds: Layer Blend Modes (photography.tutsplus.com)