gamma4scanimage(1)

💖 gamma4scanimage — the SANE era 💖

okay bestie, so this is gamma4scanimage(1), part of SANE — Scanner Access Now Easy (which, iconic name, they ate with that acronym). she's a lil command-line cutie whose whole job is making gamma tables for scanimage. no cap.

✨ NAME ✨

gamma4scanimage — create a gamma table for scanimage

🎀 SYNOPSIS 🎀

gamma4scanimage gamma [shadow [highlight [maxin [maxout]]]]

🦋 DESCRIPTION 🦋

so gamma4scanimage literally builds a gamma table in the exact format that scanimage expects. like, that's her whole thing. you get to define a gamma, a shadow, and a highlight value. you can also set the size of the table (maxin) and the max output value (maxout). very customizable, very main character.

• gamma — a floating point value, and the neutral, do-nothing value is 1.0. if you go larger than 1.0, the image comes out brighter. ✨
• shadow — this one defines the minimum input value that's actually needed to make an output value bigger than zero. shadow has to live in the range [0..maxin]. her default is 0.
• highlight — this defines the maximum input value that still produces an output value smaller than maxout. highlight must be in the range [0..maxin] and larger than shadow. her default is the same as maxin (so 16383 if nothing's set).
• maxin — defines the size of the gamma table. ngl this depends on your scanner/backend, so listen up:
  • 8 bit gamma input → maxin must be 255
  • 10 bits → 1023
  • 12 bits → 4095
  • 14 bits → 16383

the default is 16383. and to find out what value maxin needs to be for your scanner, call scanimage(1) with a very large gamma table [0]0-[99999]255 and scanimage(1) will print an error message telling you the gamma table size it actually needs. cute, right? she snitches on herself. 💅

• maxout — defines the maximum output value. take a peek at the output of scanimage -h to figure out what maxout needs to be. her default is 255.

🔥 EXAMPLE 🔥

scanimage --custom-gamma=yes --gamma-table `gamma4scanimage 1.8 0 11500 16383 255` >image.pnm

periodt. that's the whole vibe.

🌈 SEE ALSO 🌈

• sane(7)
• scanimage(1)

👑 AUTHOR 👑

Oliver Rauch

📧 EMAIL-CONTACT 📧

Oliver.Rauch@Rauch-Domain.DE

and that's a wrap, bestie 💜 this lil page is from the SANE Scanner Access Now Easy fam, dated 10 Jul 2008 — yeah she's a vintage queen but she still serves. go make some gamma tables, you got this 🫶✨