Photos come out real dark when printed on various printers

Question

Im really unsure if this is an Indesign problem or not but most everything I do is created in InDesign along with Photoshop, Acrobat, and other Adobe products.  Im just out of ideas on what the problems could be so thought I would take a crack at Adobe being the problem?  I just dont know!
When I print things out on our high end Xerox color printer, things tend to come out more on the darker side.  Its mostly noticable with photographs but it can also be seen in general solid colors also.  I generally make the printer print 85% lighter from its settings and things will usually come out acceptable.
When I send files to out digital plate maker, usually as black/grayscale, the photographs will always come out real dark.  For this, I have to over compensate by editing each photo individually so they no longer look normal on my screen, but overly faded just so it will look properly on our DPM.
This is something I have been dealing with for several years and though its basically a part of life now, I still cant stand it!  All drivers, patches, and firmware is updated, printer color is calibrated, even paid techs to figure it out...nothing!  For both our standard black and white printers, these files usually print out ok, all photos look just as good as they do on screen.
Well we just got a new large color plotter machine for printing large banners and signs.  I dont operate it but the one who does seem to know his stuff.  He said his program will only work with EPS files.  I had created a press quality PDF from InDesign that I then converted to EPS as well as creating an EPS directly from InDesign.  All files looked nice and bright on both my screen as well as his.  On his first sample printout on the plotter, the images came out dark!!!!!  Why????  We made new files where again, I overcompensated by fading the photos out bigtime to where they look horrible on screen but printed out mostly ok on the machine.
This cant be the normal way things are done, Is this an InDesign problem or what???  Any suggestions would be great because we are out of ideas!

Answer 1

I believe Xerox ships the EyeOne spectrohotometer. The companion software for that is Eye-One Match, which gets installed on your computer. I don't know if that's included. If it is, the software will lead you through adjusting the monitor and will then record a profile and associate it with the monitor. Adobe apps will use that profile to display color on screen. Each monitor needs to be profiled -- generic profiles shipped on the install disk for the monitor are useless in a color critical workflow, they match some hypothetical average monitor, or one that was pulled off the assembly line long before yours was built, and every monitor is unique in how it displays a give set of color numbers.
There should be some icc profiles on the support disks for the printers. These are the output profiles you need to target in ID, or you need to output as a standard RGB profile like Adobe RGB and let the RIP do the conversion internally to the Xerox color space.
This is a pretty complex thing to explain in detail here. You should read the Color Management section of the help files, any documentation that came with the Fiery, and I highly recommend Real World Color Management by Olav Kvern and David Blatner which is easy to read without a lot of technical jargon, and clearly explains both the theory and practice of color management in the real world (though it's now a few years old).