Images from digital cameras
Our standard advice for preparing digital camera files for Alamy is as follows:
- Use a pro-level camera with a “true” (non-interpolated) resolution of at least 6 megapixels. This will give an uncompressed file size of at least 17MB at 8 bit.
- Carefully consider your choice of lens. Lens quality is just as important today as it ever was.
- The choice between shooting in RAW, Tiff or JPEG is a matter for your own workflow. Shoot in RAW for maximum control in post-processing. If shooting in JPEG, always use the “Fine” (least compressed) setting. Modern professional DSLRs produce excellent jpegs, which are visually indistinguishable from RAW or Tiff. With lesser cameras it may be necessary to shoot in RAW to achieve acceptable image quality.
- Capture images at as low an ISO setting as practicable.
- Turn off all in-camera sharpening.
- Before working on fine JPEG’s, they should first be resaved as tiffs or another non-lossy format, e.g. psd. Never resave JPEG’s in JPEG format - this will result in permanent loss of data and degraded image quality.
- RAW files should be checked for correct exposure, colour cast, etc, and any adjustments should be made at this stage. When converting from RAW, ensure all sharpening is turned off - it’s applied by default in Photoshop.
- If necessary, rotate the image so that it’s “the right way up”.
- Do not crop your images excessively - after cropping, your file should still have an uncompressed file size at least 17MB at 8 bit.
- If necessary, interpolate (upsize) the file to 24MB using a specialist, professional software package. If you have a camera that is capable of producing an uncompressed 8 bit file size of over 24MB then leave it that size. We recommend Abobe Photoshop although other software is acceptable. If using Photoshop version 7 or higher select the bicubic option. We advise that you do not use “step” or incremental interpolation. Check your software’s default settings to ensure that all sharpening is turned off.
- Now open the image at 100%, and check for dust contamination on the sensor. This shows up as dark, circular marks - particularly noticeable in the sky and similar areas. Thoroughly check the upsized image at 100% and make any necessary corrections using the Clone Tool, Healing Tool or the History Brush technique as appropriate.
Further help
- Achieving the best results:
- Recommended camera list
- Unsuitable camera list
- Images from digital cameras
- Images from scanners
- Improving image quality
- Retouching techniques
- The Alamy Forum - the answer may be there.
- Resources - photographer tips and a directory of scanning and keywording providers.