Each BlockPhotos.Com image is coded with a unique identifying number, as explained below.

	Sample image number:  ABCD-X-1234a
	The first four letters represent the collection to which an image belongs. For example, 'FCRF' stands for "Fall Color, Reflections" and so on. On this web site, collections are organized into galleries, although a gallery may contain images from multiple collections.
	The middle character, always a letter, indicates the source format of the image. All images fall into one of the following format categories: – S = 35mm color slide – N = 35mm color negative – D = digital capture. Many digital photos on BlockPhotos.Com were captured in RAW mode with a Canon digital SLR. Others were captured as high-resolution JPEGs. Some of the older photos were captured in JPEG mode with an Olympus C-700, my first digital camera. Where available, digital RAW capture files may be licensed for stock usage in their original unmodied state. Please contact us to determine available formats for digitally-captured images. Images from analog originals have been digitized for the web using a Nikon Coolscan IV film scanner at a scanning resolution of 2900 pixels per inch. These files may be licensed for stock usage as unmodified TIFFs.
	The four numbers, '1234' in this example, are a unique identifier for the image. Numbering starts at 0001 within a collection, and increments by ones.
	Some images may have a final alpha character. If so, this indicates duplicate copies of an original in the collection. The first copy is designated 'a', the second 'b' and so on.