Outside, snow plowed along roadsides had frozen into mounds of filthy ice impossible to park on or walk across, and the sun burned wanly through portentous clouds. A streetcar carried a small brass band past, andI climbed granite steps gritty with salt as “Joy to the World” moved on. A Forensics police officer let me inside the Seaboard Building, and upstairs I found Vander inside a room bright with color monitors and ultraviolet lights. Seated at the image enhancer’s workstation, he was staring intensely at something on the screen as he manipulated a mouse.

“It’s not blank,” he announced without so much as a “how are you.”

“Someone wrote something on a piece of paper that was on top of this one, or close to on top of this one. If you look hard, you can barely make out impressions.”

Then I began to understand. Centered on the light table to his left was a clean sheet of white paper, and I leaned closer to take a look. The impressions were so faint that I wasn’t sure if I was imagining them.

“The sheet of paper found under the crystal on Jennifer Deighton’s bed?”

I asked, getting excited.

He nodded, moving the mouse some more, adjusting the gray tones.

“Is this live?”

“No. The video camera’s already captured the impressions and they’re saved on the hard disk. But don’t touch the paper. I haven’t processed it for prints yet. Im just getting started, keep your fingers crossed. Come on, come on.” He was talking to the enhancer now. “I know the camera saw it fine. You gotta help us out here.”

Computerized methods of image enhancement are a lesson in contrasts and conundrums. A camera can differentiate more than two hundred shades of gray, the human eye less than forty. Just because something isn’t there doesn’t mean it isn’t there.

“Thank God with paper you don’t have to worry about background noise,” Vander went on as he worked. “Speeds things up considerably when you don’t have to worry about that. Had a time of it the other day with a bloody print left on a bed sheet. The weave of the fabric, you know. Not so long ago the print would have been worthless. Okay.”

Another tint of gray washed over the area he was working on. “Now we’re getting somewhere. You see it?”

He pointed at slender, ghostly shapes on the upper half of the screen.

“Barely.”

“What we’re trying to enhance here is shadow versus eradicated writing, because nothing was written and erased here. The shadow was produced when oblique light hit the flat surface of this paper and the indentations in it-at least the video camera perceived shadow loud and clear. You and I can’t see it without help. Let’s try a little more enhancement of the verticals.”