It has to do with the wavelength of the X-rays vs. the size of the lead molecule and the density of it. The wavelength of X-rays is around 1 nm (nanometer). We see at ~400 nm (purple) to ~700 nm (red). For scale a nanometer is, according to wikipedia:
• 1 nm = 1 nanometer = 1000 picometers = 10 ångströms
• 1 nm — rough length of a sucrose molecule, as calculated by Albert Einstein
• 1.1 nm — diameter of a single-walled carbon nanotube
• 2 nm — diameter of DNA helix
• 3 nm — flying height of the head of a hard disk
• 3.4 nm — length of a DNA turn (10 bp)
• 3 × 8 nm — size of an albumin protein molecule
• 6.8 nm — width of a hemoglobin molecule
![[Linked Image]](http://www.folcsite.com/images/emspec.jpg)
Lead paint is lead chromate (PbCrO4). A single brushstroke will be several molecules thick. Thus it is as effective at blocking X-rays as a sheet of lead foil. Lead foil has been used in several stories to protect Clark from the effects of Kryptonite. Lead is very malleable and easy to manipulate, which is why it was used extensively for centuries until the damage to human beings could be observed.
The other major difference between Clark "seeing" with X-ray vision and X-rays as diagnostic devices is that the latter is an active system. X-ray machines emit X-rays, bombard the subject and you get a shadow picture.
Clark's vision is not active. He "sees" at one nanometer like we see at 600 nanometers.
So that's an explanation of why lead paint works just as well as lead shielding.
Artemis
