Question about Tiff files

[3Deep]

Ok very smart guys and gals, I have an artist that send me tiff sep files and there is always a large white box background, which has cuz some print problems in the rip program because see's that box and prints very fine dots.  Is is possible to save a tiff without that box, I did tell him to save the sep at print size which would make that box the same size as the art, school me here guys please

[blue moon]

either he has some very fine fill in that area (like 1-2%) that he can not see on the screen, or your work profile (if using Photoshop) is importing and changing the gradients (this is related to the dot gain settings somehow).

pierre

[Prince Art]

Hard to say without seeing the art file. One of the good things about TIFFs is that they can include layers (unlike jpgs, etc). So, if the designer saved this in layers, in theory, no printable elements should be on the same layer as a white background. And the white layer could just be deleted.

But... I did an experiment to confirm this, and Photoshop (CS5) will open the TIFF with layers, but Corel PhotoPaint (X3) will not. Corel opens with everything merged, and includes a white background even if one isn't present in the original file. (My Corel skills are rusty, so it could be I'm missing something.)

So, if you're using Corel, maybe that's introducing the problem. If you're using PS, I'd ask the designer for a layered version & if includes a white background layer, delete it.

I don't know much about RIPS, but if you can't get rid of the white, I'd use the eyedropper tool (in PS or Corel), and confirm the white is truly white. (RGB: 0,0,0, or C:0 M:0 Y:0 K:0). If it isn't, that could be the problem. I'd select & adjust that to make it 100% white. But if it's true white, and you can't get remove it, and the RIP still outputs halftones... hopefully someone else can tell you what to do! 

[ScreenFoo]

I don't know much about RIPS, but if you can't get rid of the white, I'd use the eyedropper tool (in PS or Corel), and confirm the white is truly white. (RGB: 0,0,0, or C:0 M:0 Y:0 K:0). If it isn't, that could be the problem. I'd select & adjust that to make it 100% white. But if it's true white, and you can't get remove it, and the RIP still outputs halftones... hopefully someone else can tell you what to do! 

No expert here either, but either this suggestion for the eyedropper, or if you want to get fancy, learning about a 'histogram' and how you can tell if a file's dynamic range is intact would help you find these files before the go to the RIP. 

First thing that comes to mind fixing would use an eyedropper tool as well--in PS, hit Ctrl-M for curves, pick the white eyedropper tool, and click on that white background.  That should reset your white point to whatever very light grey you are starting with. 

Exception: Noise in the 'white' background.  Zoom in a bunch, get into curves again, and darken everything a bunch--if there is noise it will jump out at you.  Either hitting that same white point eyedropper on the darkest part of the noise, or tracing around it would be my first thought if that's the case.

[Doug B]

  In Corel, simply select the object, left click on the white pallet, right click on black and
you should be good to go.

[3Deep]

Yep I use the eye dropper and the white background does have a 1 to 2 percent tint to it, so I select and delete it, photoshop picks up dang near everything

[1964GN]

1-2% can easily be taken out with Levels. Move the right slider "very slightly" to the left... just to the point where it goes to zero. It will alter your mids but 1-2% shouldn't be a big deal. If it is just move the middle slider "very slightly" to the right.

[Sbrem]

I'm with Pierre on this Darryl, there is tone in there, easily corrected in Photoshop; if there is any percentage over zero, you get dots, at zero, you get no dots...

Steve

[3Deep]

Yes you guys are right I was standing up and look down at the art on the screen at an angle and I could see the white off color, kind of crazy sitting right in front I couldn't see it at all, but standing and looking down I could see it, I'm getting old!!!!!!

[Homer]

1-2% can easily be taken out with Levels. Move the right slider "very slightly" to the left... just to the point where it goes to zero. It will alter your mids but 1-2% shouldn't be a big deal. If it is just move the middle slider "very slightly" to the right.

that's how I do it too. I use levels all the time, I can't think of the last time I adjusted anything with a curve. small bump and low % dots are gone.

[Sbrem]

1-2% can easily be taken out with Levels. Move the right slider "very slightly" to the left... just to the point where it goes to zero. It will alter your mids but 1-2% shouldn't be a big deal. If it is just move the middle slider "very slightly" to the right.

that's how I do it too. I use levels all the time, I can't think of the last time I adjusted anything with a curve. small bump and low % dots are gone.

I'm the opposite, curves only. Tomatoes tomahtoes i guess (more control in curves)

Steve

[1964GN]

I use both curves and levels depending on what I am trying to do. For me, I find levels work best if I'm just dropping those low low values OR take that 90-ish% to 100%.

I tend to use curves if I need to make more radical changes across a range of values but I have to admit, I feel more comfortable with levels.

[Sbrem]

With either tool, the eye droppers make very quick work of moving the end points...

Steve

[3Deep]

I was an all curves man , but I'm starting to use level's in the mix as well now, photoshop is monster program and I know it has many more tools I ain't thought about or even know I can use yet.