Most of the photos on this site were extracted from reference images (high-resolution tiffs, 20 to 200 megabytes in size) from the Library of Congress research archive. (To query the database click here.) Many were digitized by LOC contractors using a Sinar studio back. They are adjusted by your webmaster for contrast and color in Photoshop before being downsized and turned into the jpegs you see here.
I frequently get lost for hours in historical photos, especially if there are ads, signs or newspapers to decipher. I have been seen in the streets of San Francisco taking photos of 1920s painted ads with a 1930s camera. Yes, I'm that hopeless.