How to Prepare Digital Images for Stock Photo Libraries
Today’s digital SLR cameras are capable of producing high quality images. Below are a few tips to help you prepare your images to a standard acceptable by most stock photo libraries.
- Use a professional level DSLR camera with a true, non-interpolated resolution of at least 6 megapixels. This will give you an uncompressed image size of at least 17MB at 8 bit.
- Shoot in RAW file format for maximum control in post-production. If shooting in JPEG, be sure to use the ‘fine’ quality setting, as this provides the least amount of compression.
- Capture your images at the lowest possible ISO setting.
- Turn of all in-camera sharpening.
- If your images were shot in JPEG (fine), be sure to resave them in a non-lossy format such as TIFF before working on them. Never resave JPEG’s in JPEG format as this will result in the permanent loss of data and result in degraded image quality.
- RAW files should be checked for correct exposure and colour cast. Any adjustments you wish to make to the image should be made at this stage. Note: when converting from RAW to JPEG, be sure to turn off all sharpening.
- Do not excessiviely crop your images. After cropping, your file should still be a minimum of 17MB at 8 bit.
- Interpolate (upsize) the image file to 48-50MB. This should be done with specialist image editing software, such as Photoshop. If using Photoshop, be sure to select the bicubic option. Do not use incremental interpolation. Be sure to turn off all sharpening before upsizing your image.
- Open your image at 100% and check for dust contamination. This shows up as dark, circular marks and is particularly noticeable in large areas such as sky.
- Check the image at 100% and make any adjustments using the Clone Tool, Healing Tool or History Brush where necessary.
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Tweet ThisTwo Tips for Submitting Digital Images to Stock Photo Libraries
1. File Size
When preparing digital image files for stock libraries, it is important to be aware that File Size needs will depend on their intended uses. As a rule, stock image distributors require the largest file sizes, since final usage is unknown. Magazines tend to be more specific, although they may request Double Page (11 x 17 inches, A3 or 420mm x 297mm) for maximum flexibility in placement and cropping. Graphic designers and advertising art directors are often very specific about their file size requirements. This means it’s best for the photographer to deliver files within 10 percent of final size, unless the designer will handle resizing and output sharpening. If designers do resize images, it is best to start with a larger size and reduce it, rather than attempting to increase the resolution of smaller files. Web use and digital projection require much smaller file sizes, measured in pixels, and usually saved at screen resolution of 72 ppi. Widescreen HDTV requires a minimum of 1920 x 1080 pixels for uncropped images, though it’s common for producers to ask for more.
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Uncompressed file size requirements for print |
|
|
|
RGB TIFF at 300 ppi |
|
Double page (A3) |
50 MB |
|
Full page (A4) |
25 MB |
|
Half page (A5) |
12 MB |
|
Quarter page |
6 MB |
|
Eighth page |
3 MB |
|
Billboard |
48 MB at 600 ppi (but 300 ppi is acceptable, i.e. 24 MB) |
The current uncompressed file-size standard for commercial stock images is 48 to 50 MB. A 50 MB image file is perfectly adequate for projects requiring images larger than A3 reproduction. This is because posters, banners, point-of-purchase displays and billboards are printed at lower linescreens (lpi). As the final size for such uses goes up, the viewing distance goes down, which means the screen ruling can also go down, allowing a 50 MB file to serve all these uses. It is also worth remembering that Software RIPs (Raster Image Processors) used by wide-format printing devices have built-in algorithms that interpolate image files on the fly. This is usually a better way to resize large images than using Photoshop, and then having to handle and deliver very large files.
2. Digital Capture Quality
Sensor size and file dimensions offer only a rough guide to the final printed quality of a digital image. Digital image files may be made larger or smaller by interpolation in imaging software, which adds or removes pixels. RIP software and hardware can also interpolate during printing. Properly handled, interpolation can increase digital image files in size by as much as 400 percent. However, success depends on the qualities of the original file and the final output required. However, you need to be aware that increasing resolution through interpolation cannot add detail to a file. It may, however, prevent obvious pixelation for a smoother look. For more information on “up-rez” techniques, see ‘The Art of the Up-Res’ by Jeff Schewe.
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Sensor size |
Pixel |
Approximate Doc. Size |
8-bit |
|
17.5 MP |
3413 x 5120 |
11 x 17 inches |
50 MB |
|
11.2 MP |
2731 x 4096 |
9 x 13 inches |
32 MB |
|
6.3 MP |
2048 x 3072 |
7 x 10 inches |
18 MB |
Stock-image distributors, magazine publishers or others requesting files may specify a certain minimum size for camera sensors used to generate image files. However, it is important to be aware that pixel quality generally trumps pixel numbers. This means that a high-quality 6MP sensor will often be sufficient for 95% of intended uses, while pictures from a 10MP sensor in a point-and-shoot camera may look poor when enlarged beyond 8×10 inches at 300 ppi. This is especially so if the image was captured at an ISO exposure setting above 200. Although many publishers have standardized on 300 ppi for 150-line screens, the actual requirement is 1.3–2.0 times the line-screen resolution. So, in practice, smaller files can successfully work for a given final size.
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Calling All Photographers
Images of Contemporary Ireland
Dublin based stock photo library FotoEire is looking for photographers with images of contemporary Ireland.
FotoEire is a Dublin based photo library specialising in creating, distributing and licensing stock images of contemporary Ireland.
Their clients include advertising agencies, graphic design firms, and publishers worldwide. Their images are used by clients sourcing local relevant Irish images as well as looking to accurately represent the global marketplace in their image selection. All of their images are shot to the highest technical and creative standards and are available for download in high resolution from our website. Images created by their photographers are used everyday to sell products and services around the world.
If you have images of contemporary Ireland and would like be represented by FotoEire, you can check out their submissions guidelines here.
Did you like this? If so, please bookmark it,How ‘Crummy Weather Photography’ Inspired My Day
A few simple words of advice can make all the difference to a photographer. I had been sitting in front of the computer trying to prepare a lesson for my beginner’s photography class for over an hour with little success. I wanted to give my students something useful they could take home at the end of the evening and put into practice. But nothing was happening. The plan to go into the Wicklow mountains had been abandoned due to the rain, so there was no chance of preparing a session on photographing the local landscape as promised.
Quite by chance, while browsing incoming Tweets in my Twitter stream, I came across an enthusiastic call to visit Cass Comerford’s Crummy Weather Photography. Here, in a handful of pictures, she revealed the secret behind how she captured a beautiful image of her newborn daughter on a truly bad weather day. The bright, high-key clarity in this image was enough to remind me that it’s not necessarily the quality of the weather that makes a picture, it’s the quality of the photographer’s thought and how they use whatever is at hand to ‘paint’ with light.
(Image: Cass Comerford)
For the full story behind Cass’s photo shoot, take a look at her post on beyondmegapixels.com.
Did you like this? If so, please bookmark it,VISUAL TRENDS: When is a ‘house’ a Home?
Last night I read a report on the visual trends in stock image sales published by Getty Images. It hightlights a shift in the idea of ‘Home’. According to their analysis of client keyword searches, Getty suggests there is a move away from the idea of a house as a ‘lifestyle’ decision or an ‘investment’, to the idea of the house as Home. No longer simply a ’space’ which can be designed and managed, the Home is a place with its own set of meanings: symbols such as ‘dwelling’, ‘retreat’, ‘freedom’.
With the keyword ‘house’ now appearing as one of the top ten search terms on Getty’s website, this change in emphasis has clear implications for the stock photographer. My natural inclination is to rethink how I will look at houses when shooting stock.
Feel free to give an example of what you’ve done and share your lessons in comments below so we can all improve our photo techniques!
Take a look at Getty’s report.
‘Home: The Visual Benchmark in The Recession’ (pdf), Getty Images, 2008
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Coming Soon: ‘Professional Standards & Practices’
Over the next few months I will be writing a series of posts looking at a range of professional standards and practices for photographers. Issues covered will include digital asset management, colour profiling, IPTC metadata and photography workflow.
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