Technical Support Document 057 - 3/98
Sentinel Operation with the Accunet
Operation of the Sentinel Enlarger with the Accunet
system requires that the Master Color Balance be aligned
with your lab's standard. Please refer to the Starlite
Instruction Manual for maintaining color alignment with
your video analyzer on a daily basis.
GENERAL OPERATION: PRINTING A JOB USING ACCUNET
- Take the negative to the enlarger with it's order
number and negative number.
- Put the negative into the enlarger to prepare for
the first test print.
- Press RECALL and press ENTER to go into the Network
Recall option.
- Key in the order number and the negative number
and press ENTER.
- Wait for the display to show the job number, negative
number and film number.
Below that information, the display will show the combination
information for the various print sizes to be printed
from that negative.
Use or to scroll down that information.
The combination information is displayed in the following
way:
| # |
Qty |
Size |
Code |
|
Magnification |
|
 |
|
|
|
|
|
|
| 2 |
12 |
A>10 |
P:10.00in |
M: |
8.70 |
50mm |
| |
|
 |
|
|
|
|
| |
|
Crop |
Actual Size |
|
|
Lens |
The Quantity is the number of prints at that
size. The Crop is the same as the Crop Code from
the Accunet. The Size Code is the same as on
the Accunet. The Actual Size is the dimension
that is entered for that size code in the Sentinel Preferences
menu . The Magnification is calculated by the
Sentinel and is derived from the dimension entered for
this Crop Code and that entered for this Size Code in
the Sentinel Preferences Menu. The Lens shown
is the one set in the Preferences menu for that crop
size.
You can scroll through the listing and press ENTER
if you want the Sentinel to move to position for a particular
print in this job. If you don't want the enlarger to
move, press CANCEL. Either way, the Density, Cyan, Magenta
and Yellow data will be accepted.
Note that the exposure time will not be set from the
Accunet, but the exposure time will automatically be
increased or decreased to reach the desired target.
Make your test print. Put in the corrections at the
Accunet terminal as usual. Repeat the steps in the section
to make the second print and so on.
ACCUNET CONFIGURATION
The Size Code
When a print is recalled from Accunet, the Accunet
system simply sends a Size Code to the Sentinel. This
Size Code is the Accunet description of the print size
to be made-it is up to the Sentinel to know the actual
dimensions of the print. In other words, the Accunet
will provide the information that the print size is
code "16," but it is up to the Sentinel to
know that this is a 16" x 20" print. Thus,
it is very important that the actual dimensions (in
inches) of the print size represented by each Size Code
be entered into the Sentinel.
The actual print sizes for each Size Code can be entered
using the Edit Network Print Sizes option in the Sentinel
Preferences menu . Simply enter the 2 digit Size Code,
then the actual dimension you would like that code to
represent. Dimensions are in inches only.
You will notice that each Size Code can be programmed
with only one linear measurement, so the questions arises:
For a given print size, like 16x20, which measurement
do we use? 16 or 20 inches? The answer is to always
use the longest of the two measurements, in this
case, 20 inches. In this example, we could use the Size
Code "16" for the Accunet, but the Size Code
"16" would actually hold a measurement of
20 inches.
Be sure to enter valid sizes for all of the
Size Codes used with you Accunet system.
The Crop Code
The Crop Code is a letter used by the Accunet system
to denote what size of negative is being used to make
a particular print from the current job. Like the Size
Code, the Crop Code represents an actual linear measurement.
This measurement should represent the longest dimension
of the image area on the negative.
For instance, if we have a 35mm negative that is denoted
by Accunet as Crop "A," we should take a standard
35mm negative from production, and measure the image
area along the longest dimension. Measuring a
real 35mm negative, we find that the size of the image
area on the film is 1.466" x 0.985". So, in
the Sentinel Preferences Menu, under the "A"
Crop Size, we should enter a value of 1.466 inches,
since this is the longest of the two dimensions for
the image on a 35mm negative. Note that the actual image
size for any negative is rarely, if ever, equal to the
"advertised" size of that negative. (A 35mm
negative's image is not actually 35mm long!)
The dimensional size for each crop size can be entered
using the Edit Network Crop Sizes option the Sentinel
Preferences menu . Scroll through the list and select
the Crop Size to edit. Press ENTER and input the longest
dimension for that Crop Size, then enter the appropriate
lens to be used with that crop size.
What the Sentinel does with this information
When you recall a print over the Accunet System, the
Sentinel receives two pieces of information pertaining
to the enlarger's position for a given print: the Crop
Code and the Size Code. The Crop Code is the physical
length (Longest Dimension) of the negative's image and
the Size Code is the length of the print to be made
from that negative. The actual measurements for the
Size and Crop Codes are held in the Sentinel's computer
memory, listed by Crop Codes and Size Codes-the Accunet
system merely tells the Sentinel which of these operator-programmed
measurement values to use.
In order to set itself up for a particular print, the
Sentinel must first calculate the optical magnification
required for the print. Since Magnification is equal
to the Print Size divided by the Negative Size, the
Sentinel simply divides the measurement corresponding
to the job's Size Code by the measurement corresponding
to the job's Crop Code, then performs a "go to"
to this magnification. In short, the Accudata system
acts like an operator at the keypad who enters a negative
size, then presses the GOTO key, and types in the print
size. The lens defined in the preferences for the job's
crop code is also requested.
THE EFFICIENT ACCUNET SETUP
This section deals with the setup of the Sentinel Enlarger's
Autofocus-related Preferences for optimum operation
in conjunction with the Bremson Accudata System. The
two preferences of greatest interest here are the Network
Crop Sizes and the Network Print Sizes. Knowledge of
the Sentinel and its operation are assumed in these
instructions.
On the Accudata system, the Sentinel enlarger can retrieve
a Crop Size Code and a Print Size Code from the network.
These codes, as they are obtained from the network,
are simply "names" given to actual measurements.
These measurements are set by the operator of the Sentinel
Enlarger to reflect the actual physical sizes of all
Crop Sizes and Print Sizes used with the system.
When a job is recalled from the network, the Sentinel
Enlarger will calculate the magnification for the print
so as to make the size of the negative in use (designated
by the Crop Code) fit exactly into the print size at
the baseboard (designated by the Printsize Code).
To make the system work in the darkroom, the operator
needs to program Crop Size and Print Size values that
result in usable, printable magnifications at the enlarger.
These values may or mat not be the actual physical measurements
of the negatives or prints being made, but actual measurements
are a good place to start.
The automatic nature of the Sentinel system is best
utilized not by making the enlarger precisely fit the
negative's image into the area of the print paper, but
by having it setup to a magnification that the operator
would use for that print job in any case. Usually this
means cropping the image for a full coverage of the
paper.
MAKING THE SENTINEL WORK EFFICIENTLY WITH ACCUNET
1. The first step in setting up to work efficiently
is to enter the actual physical dimension of a negative
you normally use in production. For instance if
we use a "G"-Crop, we want to make a very
accurate measurement of it's actual image area, not
the entire piece of film. If you use cropping cards,
you should measure the hole over which the negative
is mounted. In either case, always use the longest
dimension of the image area for the Accunet Crop
Size.
Once this measurement is made, enter the value (in
inches), into the Edit Network Crop Sizes menu for Crop
G. Remember that the Sentinel requires inches expressed
in decimal equivalents (ex: 1¾" = 1.750")
for these values.
2. Next, we need to determine and enter the initial
Print Size code measurements using the negative
from step 1. Start by making a list of all of the Size
Codes that are used on your lab's Accunet network. Also
gather all easels that are used for the various print
sizes in this list, as well as a piece of waste paper
for each size. Using your negative, for each of the
Print Sizes on the network, perform the following steps:
- Load your negative in it's carrier into the Sentinel.
- Setup the paper and its easel for this size of print.
- In Autofocus Mode, compose the print as you normally
would, allowing for "bleed" and coverage
of the width of the image. Remember to select any
easels that are changed for different print sizes.
- Once you have sized the print to taste, write down
the resulting magnification on your list. The magnification
can be read straight from the Sentinel keypad screen.
(If the keypad is reading a print size instead, press
the GOTO key until the display reads "Magnification,"
then press Enter.)
- Calculate the Sentinel/Accunet print size for this
size of print. Use the formula:
PRINTSIZE = NEGATIVE_SIZE x MAGNIFIATION
- Write the resulting Printsize on the list next to
the Size Code or this print.
- Repeat this for all Sizes until each Size Code on
your network has a corresponding print size measurement
value.
- Print Sizes in the Sentinel System are always expressed
as the longest dimension of the print. For instance,
the Sentinel "knows" an 11x14 print as 14.000
inches.
- Once you have all your Size-Code values, enter them
into the Edit Network Print Sizes menu. Remember that
the Sentinel requires inches expressed in decimal
equivalents (ex: 24¼" = 24.250") for these
values.
You may want to program a few jobs on the Accunet System
to test your Size Code setups for this Crop size. Such
a job should have prints at all sizes, but from only
the one Crop Size used here.
3. We will now setup the other Crop Sizes using
the print sizes we have determined in step 2. You
will need a set of negatives or cropping cards, with
one of each Crop Size used on your network. If you use
cropping cards (cards with no negatives work O.K.),
use these instead of bare negatives. Choose a "normal"
print size, one that you use most often, or is easy
to view. For each Crop Size, perform the following:
- Load a negative of the Crop Size being setup. Remember
to use the select the appropriate carrier for this
negative.
- Setup the paper and its easel for the "normal"
print size.
- In Autofocus Mode, compose the print as you normally
would, allowing for "bleed" and coverage
of the width of the image.
- Once you have sized this print as you normally would
in production, write down the resulting magnification.
The magnification can be read straight from the Sentinel
keypad screen. (If the keypad is reading a print size
instead, press the GOTO key until the display reads
"Magnification," then press Enter.)
- Calculate the measurement for this Crop Size, using
the formula:
CROP_SIZE = PRINT_SIZE / MAGNIFICATION
The "Print_size" is the measurement you
entered in the Sentinel for the "normal"
Size. The resulting printsize setup you now have should
be very close to the one you did in the last section
for this size of print (same bleed or cropping as
before).
- Enter the resulting measurement value for this Crop
Size in Edit Network Crop Sizes. Also, Enter the lens
that is normally used to make a print from this size
of negative.
- Repeat this for all Crop Codes on your network.
You should have entered a value for every Crop Code.
At this point, the system is ready to try out. Either
program various jobs into the Accunet, having all combinations
of Crop sizes to Print Sizes, or recall production jobs.
For each job, check that the Sentinel sets itself up
to a "workable" size.
MAKING CORRECTIONS…
Chances are that during testing or at some point in
production, you will want to adjust the magnification
to which the Sentinel has set itself up to for a particular
job. To change the setup for a particular job, we can
either alter the Crop size or the Print Size. There
are, however, limitations to what you can do here: if
you change the Crop Size, all jobs printed from
this Crop will be affected. Also, if you change the
Print Size, all future jobs made to that print
size will be altered. Thus, it is beneficial, if a job
sets up to an undesirable size, to know which measurement
to alter as a solution.
Some guidelines
If the negative being used has a different aspect ratio
from other negatives, use the Crop size to affect the
change.
If the print size is unique in that it has an odd aspect
ratio, use it's Print Size value to affect the change.
Ask whether this size of Crop tends to have trouble
where the other Crops are O.K. If this is the case,
change its value, since that change may help other print
sizes made from this Crop as well.
Likewise, if the Print Size for this job seems to have
trouble than the others, use its value to make the change.
If in complete doubt as to which value to use, always
use the Print Size. Favoring one value over the other
will help prevent size value runaway, where you correct
one print using Crop, then correct another print from
that Crop, using Size, then correct another print of
that size, using Crop… eventually, this hap-hazard
system will form a loop, and your values will be far
from what they were intended to be-actual physical measurements
of the materials involved.
Correcting using a Crop size
If you call up a print and it is off by a certain distance
in length at the baseboard, you can calculate the amount
by which to change the Crop Size value:
CROP_CHANGE = DESIRED_CHANGE_AT_BASEBOARD /
MAGNIFICATION
The Magnification value to use is that which is on-screen
for this setup.
Correcting using a Print Size
Once you know how much the print needs to change in
length, simply alter the printsize value by that amount,
in inches.
ACCUNET COMMUNICATION DIAGNOSTICS
There is one diagnostic test to aid in finding data
transmission problems. In the Sentinel Preferences menu
and select the Network Diagnostic Mode option. Set the
option to Active. Now, when a network job is performed,
a number of messages and data strings will be displayed
on the display during the recall process.
If you have questions or problems with this procedure,
please contact ZBE at the email, address or phone numbers
below.
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