Digital BW, The Print

Hi,
2 questions:
1. How are the IJC "AIMS" determined for any particular inkset/paper
2. How are the "AIMS" inputed into the program so that they appear?
Thanks
Kevin Logan

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "klog52756" <klog52756@y...> 
wrote:
> Hi,
> 2 questions:
> 1. How are the IJC "AIMS" determined for any particular inkset/paper
> 2. How are the "AIMS" inputed into the program so that they appear?
> Thanks
> Kevin Logan

Hi Kevin,

The AIMS are based on measured values of dMin (the plain paper) and dMax
(paper with the max amount of ink).  You just evenly divide the range into
the number of steps you want.  The tricky thing is that density is a 
logarithmic scale.  If you were to look at it in L* space (from LAB) it would
be mathematically linear and also linear in human perception.

Roy
www.harrington.com

Hi Roy & thanks for the info.
Measuring the Dmin/Dmax makes sense to me, and dividing it by the 
number of steps I am measuring makes sense to me, AND I have a vague 
recollection of what a logarithm is, BUT, when I was young & smart 
it surely would have made total sense to me.  Now I am old & stupid 
& just a photographer, and really don't remember how/what to do with 
logarithm.  I "seem" to remember that a logarithm is "based" on 
another number, say base 10, or something.
Anyway, if you don't mind, could you expand on what you mean by 
logarithmic, and help out an aging feeble minded photographer 
<smiling>.
Lastly though, even with your help, and when I can figure this out 
and get my numbers, I still can not figure out how to input 
the "AIMS" into IJC.  At the moment all my "AIMS are 0.00. The 
sample profiles they provide have other numbers (presumably along 
the lines of what I am looking for), but I can not figure how/where 
within the program these "AIMS" are inputed.
Cheers Roy,
Kevin Logan

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Roy 
Harrington" <roy@h...> wrote:
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "klog52756" 
<klog52756@y...> 
> wrote:
> > Hi,
> > 2 questions:
> > 1. How are the IJC "AIMS" determined for any particular 
inkset/paper
> > 2. How are the "AIMS" inputed into the program so that they 
appear?
> > Thanks
> > Kevin Logan
> 
> Hi Kevin,
> 
> The AIMS are based on measured values of dMin (the plain paper) 
and dMax
> (paper with the max amount of ink).  You just evenly divide the 
range into
> the number of steps you want.  The tricky thing is that density is 
a 
> logarithmic scale.  If you were to look at it in L* space (from 
LAB) it would

> be mathematically linear and also linear in human perception.
> 
> Roy
> www.harrington.com

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "klog52756" 
<klog52756@y...> wrote:
> Hi Roy & thanks for the info.
> Measuring the Dmin/Dmax makes sense to me, and dividing it by the 
> number of steps I am measuring makes sense to me, AND I have a vague 
> recollection of what a logarithm is, BUT, when I was young & smart 
> it surely would have made total sense to me.  Now I am old & stupid 
> & just a photographer, and really don't remember how/what to do with 
> logarithm.  I "seem" to remember that a logarithm is "based" on 
> another number, say base 10, or something.
> Anyway, if you don't mind, could you expand on what you mean by 
> logarithmic, and help out an aging feeble minded photographer 
> <smiling>.

You really don't need to do anything about it.  If you look at any of
the examples and plot the values, they are a curve rather than a
straight line -- the curve is based on a logarithmic shape.

> Lastly though, even with your help, and when I can figure this out 
> and get my numbers, I still can not figure out how to input 
> the "AIMS" into IJC.  At the moment all my "AIMS are 0.00. The 

I've not used IJC so I'm not sure of the specifics, but the idea is you
should measure a paper white density and a pure black density.
Both of these numbers must be entered, IJC will then fill in all the
intermediate values according to the "logarithmically even" values.

Roy

> sample profiles they provide have other numbers (presumably along 
> the lines of what I am looking for), but I can not figure how/where 
> within the program these "AIMS" are inputed.
> Cheers Roy,
> Kevin Logan
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Roy 
> Harrington" <roy@h...> wrote:
> > --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "klog52756" 
> <klog52756@y...> 
> > wrote:
> > > Hi,
> > > 2 questions:
> > > 1. How are the IJC "AIMS" determined for any particular 
> inkset/paper
> > > 2. How are the "AIMS" inputed into the program so that they 
> appear?
> > > Thanks
> > > Kevin Logan
> > 
> > Hi Kevin,
> > 
> > The AIMS are based on measured values of dMin (the plain paper) 
> and dMax
> > (paper with the max amount of ink).  You just evenly divide the 
> range into
> > the number of steps you want.  The tricky thing is that density is 
> a 
> > logarithmic scale.  If you were to look at it in L* space (from 
> LAB) it would
> > be mathematically linear and also linear in human perception.
> > 
> > Roy
> > www.harrington.com