Dolev 800 - Application Issues -
Setting RES/Intensity

Overview
Calibration Work Flow

Overview

To guarantee high quality exposures, a unique laser intensity is required for each plotting resolution (60, 80, 100,120, 140 dots/mm). If the laser intensity is too low, the exposure is too light and quality is lost. The black areas are not uniform thin lines and small text may disappear. If the laser intensity is too high, thin lines may become too thick and small text may be covered. The life of the laser is also shortened.

Each type of film requires a unique laser intensity. If you switch to a new type of film, you must expose several strips of film and check the density. You want to ensure that the exposure is still of the same high quality. Each film manufacturer has slightly different specifications for various types of film. You must check which laser intensity on the Dolev yields your desired exposure results.

Calibration Work Flow

General
Step One: Preparing Exposure Strips
Step Two: Setting an Exposure Resolution
Step Three: Exposing the Strips
Step Four: Measuring Density on the Strip
Step Five: Recording Laser Intensity
Saving New Laser Intensity as Standard (Default)

General

To calibrate laser intensity, perform the following steps for each exposure resolution.

1. Prepare the strips of film at each intensity.
   
   
2. Set an exposure resolution for the strips.
   
   
3. Expose the strips.
   
   
4. Use a densitometer to measure the density on the exposed strips of film. A density between 3.8 and 4.2 is acceptable. Make sure that it is according to film manufacturer recommendations. Write down on paper the intensity used to expose the best black strip of film at each resolution.
   
   
5. Adjust the imagesetter with the new laser values. You enter the intensity for each plotter resolution in the Resolution Intensity Table.

Step One: Preparing Exposure Strips

Overview
Plotter Setting on the Whisper
Plotter Setting on the Dolev PS
Plotter Setting on the Dolev PS/M

Overview

To begin, expose film strips at laser intensities between 2000 and 10230. Find the best laser intensity for each exposure resolution. If you want to use the Half Resolution option (see Excurve Handling), repeat the entire procedure described using the Half Resolution option.

A CreoScitex engineer sets these values for each resolution. Check intensity if you experience reduced exposure quality. The Calibration menus are listed below:

Exposure Strips Screen

1. Auto Plot - Origin Step
   
2. Auto Plot - Write Intensity
   
3. Auto Plot - Resolution

Auto Plot - Write Intensity

1. Write Intensity Start Value: 2000 End Value: 10230 Step: 800
   
2. Strip Height = 5
   
3. Origin Step = 35
   
4. Number of Strips = 11
   
5. CAL-PLOT Parameters

Plotter Settings Screen

1. Machine
   
2. CalPlot
   
3. Strips
   
4. Data
   
5. Utility

Cal Plot Parameters Screen

Plotter Setting on the Whisper

Access to the Plotter Setting function, required for Calibration, is different on the Whisper and Dolev PS workstation.

To find the proper intensity, select Set-Up <F2>.

Select 3. I/O Devices from the Set-Up menu.

Select 2. Plotters from the I/O Settings menu.

Select 1. Plotter Setting.

Plotter Setting on the Dolev PS

a) Select Set Up in the utility strip.
       
b) Select I/O Devices in the Set Up menu.

c) Select Plotter Setting in the I/O Devices menu

How to Use the Dolev Menus

a)     Enter the number that corresponds to the entry on which you want to work.

b)     Enter E (for Exit) to return to the previous menu. Enter Exit as necessary to return to the desired menu.

c)     Some selections require you to supply values: film length, laser speed, film thickness, etc. In this case, a           line of text appears at the bottom of the screen prompting you with the available options. For example:           Cassette Size: (Auto Calculated/Small/Medium/Large):

The remainder of the steps are identical in both the Whisper and the Dolev PS workstation.

Plotter Settings Screen

1. Machine
   
2. CalPlot
   
3. Strips
   
4. Data
   
5. Utility

1.    Select 3. Strips from the Plotter Setting menu. You can set values such as intensity, resolution, line fix value, and facet fix value.

Exposure Strips Screen

1. Auto Plot - Origin Step
   
2. Auto Plot - Write Intensity
   
3. Auto Plot - Resolution

2.    Select 2) Auto Plot - Write Int. from the Strips menu to set the laser intensities and the size of the exposure          strips for one resolution.    

3.    Enter the laser intensity values of each strip:

       Create 11 exposure strips with Write Intensities between a Start Value of 2000 and an End Value of               10230. The exposure intensity increases in steps of 800.

    Set a Strip Height of 5 mm. The distance between adjacent exposure strips is referred to as the Origin. Set an Origin Step of 35 mm.
       
Auto Plot - Write Intensity

1. Write Intensity Start Value: 2000 End Value: 10230 Step: 800
   
2. Strip Height = 5
   
3. Origin Step = 35
   
4. Number of Strips = 11
   
5. CAL-PLOT Parameters

Remember that you must find an acceptable laser intensity for each resolution. Use the CAL-PLOT function to change the resolution (60/80/100/120/140).

The values on the Auto Plot menu are sample values only. The values you enter depend on personal preference and film type.

You select the exposure resolution under CAL-PLOT.

You still need to define the size of the exposed file, and select a resolution.

Plotter Setting on the Dolev PS/M

Step Two: Setting an Exposure Resolution

1.    Select 5) CAL-PLOT Parameters to select a resolution. The file you create is a synthetic file that does not require the host workstation.

Cal Plot Parameters Screen

1. Plot Size:     [H,W]     = 100.00 100.00
   
2. Resolution: [H,W]     = 100.00 100.00
   
3. Offset     [H,W]     = 0 0
   
4. Pattern Type     = Slash
   
5. Pattern Period     = 8
   
6. Pattern Width     = 1
   
7. Pattern Start     = 1
   
8. Dolev 800 Parameters

Enter D to return to the original (default) values. Enter R to run.

2.    Each CAL-PLOT menu item has options. Select the option in each menu to perform the desired operation. Each option is described below.

    CAL-PLOT Options

3.    Select 9. Dolev 800 Parameters. Do not change any of the values. Only CreoScitex Customer Support personnel are authorized to change the parameters. The menu contains the following parameters:

Note: Set item 10, Minimum Film Feed, to 380mm for output to cassette, or to 400mm to output film to a conveyor.

Step Three: Exposing the Strips

1. Press R(un) at the bottom of the CAL-PLOT Parameters menu to begin exposing the strips according to the values on the table.
   
   Select (1-9 / Def / Run / Messages / Exit) ?
   User Request: [ R ]
   
   
2. Develop the film strips.
      
   
3. Find an acceptable density on the film.

Step Four: Measuring Density on the Strip

1. Place the exposed film on a light table. Use a densitometer to find the density of the darkest cell on the film. The reading must be between 3.8 and 4.0. A good indication of which exposed strip has the best density is to look at the light strip that is exposed together with the black strip. Ideally, the transparent area should be 0%, and the black area should be 100%
   
   Finding an Acceptable Laser Intensity
   
   The shape on the gray strip, whether defined as a dot or line, must be smooth, sharp and of high quality. When you find the gray strip with these qualities, you willfind the desired density on the black strip with which it is paired.
   
   
2. Find and write down the laser intensity that yields the proper density. The next step is to set the imagesetter to work with the new laser intensity (resolution intensity).

Step Five: Recording Laser Intensity

To record the new laser intensity, exit the Auto Plot menu and return to the Plotter Setting menu and enter the new intensity on the machine table.

1. Select 1) Machine
          
   
2. Select 2) Operator Tables.
   
   
3. Select 1) Res Intensity from the Operator Tables menu. At this point, you must select a Res Intensity Table. Perform one of three actions:
          
       a) To update an existing table
       b) To replace an existing table
       c) To create a new table
   
   
4. The second Res Intensity menu appears. Complete the menu with as much information about the supply media (film/paper/plate) as you can provide.
   
   Res - Intensity Menu
   
   1.     Material: Film
   2.     Manufacturer: Dupont
   3.     Catalog Number
   4.     Batch Number
   5.     Media Thickness: 4
   
   This step is critical, as it allows the software to automatically select the correct exposure intensity for your specific supply media.
   
   
5. When you complete the form, press the function key, Next. The next menu consists of two sets of values: the exposure resolution and the laser intensity.
   
   The Laser Intensity values are divided into two parts: Full Resolution mode and Half Resolution mode. The Full Resolution mode is referred to as L Speed Int. The Half Resolution mode is referred to as H Speed Int.
   
   Resolutions are generally entered in dots/mm.
   
   Building a Res Intensity Table
   
   
6. To enter your list of laser intensities for each resolution, select the highlighted number that corresponds to the resolution you want to set. Select 1) to select a blank table.
   
   Complete the table until you have entered all of the resolution intensities for each of the resolutions you have checked.
   
   Generally, once you build a table for a specific film type, you do not return to this menu.
   
   
7. Press Exit until you return to the Main Functions menu. When you are finished, be sure to perform an update.
   
   
8. Return to the CAL-PLOT menu and select a new resolution. Repeat all of the steps for each resolution.
   
   Note: To work in Half Resolution, select the CAL-PLOT Half Resolution Yes option. Begin the exposure process.

Saving New Laser Intensity as Standard (Default)

If you want the new laser intensity to be the standard value you use every day, do the following:

1. Exit to the Plotter Setting menu.
   
   
2. Select Machine. Select 5) Save/Restore NVM from the Machine menu.
   
   
3. Select 1) Save NVM on Host Disk, or 3) Save NVM on PC Diskette.
          
   
4. Fill in a file name. Answer Y(Yes) to the query, Save? Press Enter.
   
   
5. Exit to the NVM menu. Exit to the Machine menu. Exit to the Plotter Setting Menu. Exit Plotter Setting. You receive the message "Press any key to continue."
   

Note: The values on the Res Intensity Tables are saved. However, the information entered on the Cassette NVM menu for the Large/Medium/Small cassettes is not saved. It is up to you to update the cassette information each time you change the cassette or type of consumable on the cassette.