Difference between 1 bit & 8 bit tiffs?

[andyskandie]

What is the difference in the 1 bit & 8 bit tiff as far as outputting to film? I have never heard of using 1 bit tiffs but have had a customer ask about using them recently?

 

[KevinC@EFI]

The "Friday" answer would be: 7 bits.

A 1-bit TIFF is either black or white... there's no gray. i.e., there's 1-bit of computer data for each pixel in the file, and one bit can only tell you "on" or "off". This is what's needed to image the final film or plate itself, and is usually either linework, or pre-screened data. It's what a RIP would generate from your original artwork before platemaking.

8-bit TIFFs are not printable as-is... they're gray-scale images that need to be RIPped into halftone (i.e. 1-bit) before printing. You can use 8-bit TIFFs in InDesign/Quark/etc., but you can't send them directly to your CTF or CTP.

I hope that helps.
Kevin.

 

[gordo]

What is the difference in the 1 bit & 8 bit tiff as far as outputting to film? I have never heard of using 1 bit tiffs but have had a customer ask about using them recently?

1 bit means black and white, on/off - no gray levels. Usually 1 bit tiffs means screened files - basically what gets imaged on a printing plate. The files could also be text only.

gordon p

 

[disbellj]

8-bit TIFF is not screened yet.

1-bit TIFF is screened (unless it's a solid, like a black logo). You can make 1-bit screen in PhotoShop if you know the angle of your black separation. This is not done much anymore though.

Everything is screened to 1-bit TIFF when going to film or plate.

When CMYK printed together, these screens overlapping at different angles makes the illusion of continuous tone being printed.

Regards,

Don

What is the difference in the 1 bit & 8 bit tiff as far as outputting to film? I have never heard of using 1 bit tiffs but have had a customer ask about using them recently?

 

[andyskandie]

I like the Friday answer.
Thanks for your help and have a great weekend!

 

[FKarlone]

1 Bit

1 Bit

1 bit = 2 shades of gray, 8 Bit = 256 shades of gray, 16 Bit = 65,535 shades of gray

 

[John Clifford]

1 bit = 2 shades of gray, 8 Bit = 256 shades of gray, 16 Bit = 65,535 shades of gray

Sorry, but 1-bit is NOT 2 shades of gray. A single bit is either on or off. Thus black or not black. There is no gray involved.

And in printing (like on a press) there are also no shades of gray, so all printing plates/film are 1-bit. Gray is achieved via screening.