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Digital BW, The Print

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What's the practical difference between a curve and a profile?

What's the practical difference between a curve and a profile?

2003-09-14 by dave_in_gva2001

Hello everyone,

Longtime lurker firsttime poster.

I'll begin by saying thank you to so many of you who have unknowingly 
pushed me quite far along on a learning curve regarding black and 
white printing.

I am about to come back into photography with a digital SLR platform, 
having abandoned my large format gear and darkroom for 'small' things 
in the form of a happy marriage and children over the last 12 years.

I expect to be printing both black and white and colour on an Epson 
2100, and expect to be spending a fair chunk of change in the next 
few months on what I hope will turn out to be well researched choices.

One of the things I'd like to get a better understanding of is the 
effective difference betweeen a curve and a profile. My understanding 
is that both are created by measuring (with a densitometer and 
spectrophotometer respectively) a specific output printed on a 
specific paper with a specific printer. 

Since both seem to be linked to a specific printer/paper 
configuration and combination, does one need to have one's 
printer/paper profiled or can one rely only on an adjustment curve 
provided it was made for the specific paper you are interested in 
(and printer obviously)?

I will be purchasing a CRT monitor and an Eye-One Display for monitor 
calibration but will not have profiling capability.

Part of the rationale for the question is that I've had a very 
helpful correspondence with Daniel Staver offline about my black and 
white printing options. While Daniel has been using the UT's on the 
2100 he raised a couple of times the non-neglibible advantage of the 
Septones system inasmuch as 50 or so papers are profiled.....

The UT's are substantially less expensive than the Septones and there 
are curves available (presumably for specific papers on the 2100) - 
which brings me back to my question. If I have these curves do I 
actually need profiles if I stay with those papers?

Hope that's clear, and thanks again for being such a helpful forum,

Dave Meddings

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