Screen image=raster image process (RIP)?

[mangcang]

I mean if I use inkjet or laser to print an image from Photoshop or whatever, the image need screening before it printed. Is the same process and result as RIP does? Thanks

[gordo]

I mean if I use inkjet or laser to print an image from Photoshop or whatever, the image need screening before it printed. Is the same process and result as RIP does? Thanks

No, an inkjet does not use halftone screening. Ink droplets are sprayed on the substrate as needed to form the image. The result only looks like an FM screen. The sprayed droplets can be organized to simulate halftone dots if that is required.

best, gordon p

[prepressing]

Can you give more details on what exactly you are trying to do and what you want the end result to be?

You do not mention if you are printing to film (monochrome output using only black) or if you are printing in full color. As Gordon has mentioned the inkjet is basically printing what is sent to it. If you want to control the screening in the file then you may attempt to do this from within RIP software or the design application itself.

[mangcang]

Can you give more details on what exactly you are trying to do and what you want the end result to be?

You do not mention if you are printing to film (monochrome output using only black) or if you are printing in full color. As Gordon has mentioned the inkjet is basically printing what is sent to it. If you want to control the screening in the file then you may attempt to do this from within RIP software or the design application itself.

I learn that if we print an image using offset print, we should screen the image before it printed. The question is if I want to use the inkjet or laser printer to pirnt the same image, do I still need to screen it before it printed? why or why not. Thanks

[mangcang]

No, an inkjet does not use halftone screening. Ink droplets are sprayed on the substrate as needed to form the image. The result only looks like an FM screen. The sprayed droplets can be organized to simulate halftone dots if that is required.

1,So the image printed out from inkjet is continuous tone image? How about laser?
2,How do I determine whether or not screen the image before I send them to different print method?(inkjet vs laser vs offset) Does only offset need image screen?
3,Where to screen image? I found I can screen the image in photoshop. Is the same function as the RIP does? Is there any conflict between them?

Hope you not overwhelmed my questions
Thanks

[gordo]

1,So the image printed out from inkjet is continuous tone image? How about laser?
2,How do I determine whether or not screen the image before I send them to different print method?(inkjet vs laser vs offset) Does only offset need image screen?
3,Where to screen image? I found I can screen the image in photoshop. Is the same function as the RIP does? Is there any conflict between them?

Hope you not overwhelmed my questions
Thanks

1- No the image printed out from inkjet is not continuous tone image. More droplets of ink are used to make darker tones like an FM screen. But the image, AFAIK, is not halftoned in the same sense that it would be if going to an offset plate. If you mean a black and white toner (electrophotograhic) printer by the term "laser" then the conversion to a halftone screen is done using a spot function Postscript (or other PDL) by the RIP.

2. Unless you are doing a special effect screen (e.g. like these: Quality In Print: Custom Halftone Dots or these http://qualityinprint.blogspot.com/2...e-screens.html ) you should NOT be doing any halftone screening in Photoshop.

3. The halftone screening in Photoshop can be used for black and white images but is no good at all for color work. Even though it does the same thing as a proper RIP, the screening technology in PShop is just too unsophisticated. If you do halftoning in PShop then the final bitmap that you create must have a resolution that is an even divisor of the resolution of the final output device. I.e. if you will be imaging to a 2,400 dpi CtP device then the resolution of your bitmap can be, 300, 600, 800, 1200, or 2400 dpi at 100% reproduction. The bitmap should not be resized.

hope this helps, gordon p

[mangcang]

1- No the image printed out from inkjet is not continuous tone image. More droplets of ink are used to make darker tones like an FM screen. But the image, AFAIK, is not halftoned in the same sense that it would be if going to an offset plate. If you mean a black and white toner (electrophotograhic) printer by the term "laser" then the conversion to a halftone screen is done using a spot function Postscript (or other PDL) by the RIP.

2. Unless you are doing a special effect screen (e.g. like these: Quality In Print: Custom Halftone Dots or these Quality In Print: Creating crazy custom halftone screens ) you should NOT be doing any halftone screening in Photoshop.

3. The halftone screening in Photoshop can be used for black and white images but is no good at all for color work. Even though it does the same thing as a proper RIP, the screening technology in PShop is just too unsophisticated. If you do halftoning in PShop then the final bitmap that you create must have a resolution that is an even divisor of the resolution of the final output device. I.e. if you will be imaging to a 2,400 dpi CtP device then the resolution of your bitmap can be, 300, 600, 800, 1200, or 2400 dpi at 100% reproduction. The bitmap should not be resized.

hope this helps, gordon p

Thanks, gordon. Impressive. Have a good weekend