For exposure and process control of Xingraphics positive thermal CTP plates

Instructions for

Xingraphics Positive Thermal CtP control strip⊙ Xingraphics_DigiControl V3.5

High quality thermal CtP plate manufacturerChengdu Xingraphics Co., Ltd.Torch Power Harbor Complex, No. 7, North Block, 269 San Se Road JinJiang Industrial Park, Chengdu, Sichuan, 610063, P.R.China

Tel +86 28 8592 5222 Fax +86 28 8592 5225 Email: info@xingraphics.com www.xingraphics.com

CATALOG>>> Instruction of Xingraphics CTP output control strip [0]

>>> Preface [2]

>>> RIP information [3]

5. Concentric boxes [15]

6. Scale [16]

6.1 Vector scale [16]

6.2 RIP scale [16]

6.3 Comparrison beween vector and RIP scale [16]

7. Note in use [17]

8. Copyright clarify [18]

1. Xingraphics star target [4]

1.1 Positive/Negative spots [4]

1.2 Positive/Negative lines [5]

1.3 Positive/Negative elliptic slice [6]

1.4 Control lines [6]

2. Exposure and processing control zone [7]

2.1 Processing control [9]

2.2 Exposure control [11]

2.3 Note [12]

3. Fine lines for exposuring [13]

4. Concentric circles [14]

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This strip is used to monitor the exposure and processing conditions when using FIT series plates. It contains the following 7 areas:

1 RIP information；

2 Xingraphics star target；

3 Exposure and processing control zone；

4 Fine lines for exposure；

5 Concentric circles；

6 Concentric boxes；

7 Scale。

It can help you to �nd the proper exposure and processing settings using the 7 areas listed above, by showing you the plate reproduction capability under certain conditions (�xed plate-setter, processor, chemistry, plate, work-�ow software and so on). Moreover, this control strip can be used to maintain desired output quality.

PREFACE

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RIP information is added to the control strip so that screening and resolution can clearly be seen on the plate as this may change depending on the job requirements. The RIP information indicates all the RIP settings which are applied during the imaging of the plate. For instance: resolution_2400dpi; screening method_ AM, SQ dot; screening 200lpi.

1RIP INFORMATION

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1.1 1.1 POSITIV/NEGATIVE SPOTSShown on the lift:

These positive/negative spots have irregular shape and distributed rule. The spots increase from 1 to 4 pixels from edge to center. Some irregular tiny spots are mixed around the center (the spot size is increasing with the distance to center).

If the exposure and processing settings are correct, the irregular spots can be seen clearly as well as the tiny spots distributed around the end of lines that indicate the tiny dot reproduction is exceptional.

Ideally, the positive and negative spots should be the same size when compared against each other. But improper exposure and or processing settings would show as non-equal sizes. For example: over exposure and or over development would cause the positive spots to become smaller and the negative spots to be bigger. Also, the smaller spots at the edge of the positive area will disappear leaving fewer spots towards the center.

During production, the plate-setter and processor can have some �uctuation so that the1) Tiny spots at the edge of the area is clear; 2) The number of positive spots is not equivalent to the negative spots3) However, the corresponding positive/negative spots should be the same size when taking the center-line as your basis.The output quality would be considered consistent and stable within this range.

1. 1. XINGRAPHICS STAR TARGET

The star target is made up of four parts: positive/negative spots, positive/negative lines, positive/negative elliptic slice and control lines. The reproduction of these four parts re�ects the reproduction of image on the plate. A magnifying glass is necessary to accurately evaluate this area.

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1.2 POSITIVE/NEGATIVE LINESShown on the top:

The area between the two red dotted lines is full of positive and negative lines, including horizontal, vertical and oblique lines. Normally, you can see lines that are clear and continuous. It re�ects the �ne lines reproduction capability of plate-setter.

Two contiguous lines (1 positive, 1 negative) is considered one group. The thickness increases from 1 to 3 pixels and then decreases to 1 pixel at 1 pixel intervals from group to group with this repetition.

The horizontal and oblique lines will be broken into many sections with improper plate-setter settings. If so, plate-setter may need some adjustments to reproduce the lines correctly.

During production, the plate should meet the requirements below:

1) Reproduction of all the positive/negative lines correctly.

2) The thickness of the positive line is the same as the negative line in one group.

The output quality is considered consistent and stable within this range.

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1.3 POSITIVE/NEGATIVE ELLIPTIC SLICEShown as the �owing �gure:The area between the two red dotted lines is mainly constructed with 0.046mm positive/negative array. We assess the reproduction by evenness, sharpness and uniformity of this slice. Normally, the grain and exposure accuracy will a�ect the reproduction of this elliptic slice.

1.4 CONTRAL LINESAs �gure：Rays are spread outward from the center of the sector and those rays can be used to assess �ne line reproduction. The three ruler lines are start point of the ray and the thickness is 1 pixel on the position of intersection of sector and ray.

The laser state, exposure energy, processor state and process condition could a�ect the reproduction of those �ne lines.

During production, plate has to meet the requirements below:1) The start point of the ray at the inner sector should show good �ne line reproduction.2) If the �ne line reproduction is visible within the three ruler lines, it indicates the plate has excellent detail reproduction with proper exposure and processing conditions.

The plate quality is considered stable and secure when the two above requirements are met.

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2EXPOSURE AND PROCESSING CONTROL ZONE

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Shown above:Detailed view shown on right:

The background is full of 8*8 pixel dots while the “X” has smaller dots. The dots within the “X” decrease in size from left to right side in the upper line of X’s or from right to left side in the lower line of X’s. There are 5 patches in total, the outer most left on the upper line or outer most right side on the lower line, share the same dot with the background which is convenient for comparison. The below group is generated by rotating the �rst group by 180°.

The performance and sensitivity are di�erent due to dot size, which could be used to assess whether the exposure and developing is proper or not.

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2.1 DEVELOPING CONTROL

The positive thermal CTP coating is dissolved in the developer after exposure. If the processing settings are appropriate, the coating, imaged by the laser, will be dissolved when the plate is passed through the chemistry while the un-imaged area should not be dissolved and should su�er very little chemical attack. The smaller dots are more sensitive to the chemical bath than the larger dots, so we can assess the develop condition by comparing the appearance of “X” with background.

2.1.1 OVERDEVELOPIf the plate is overdeveloped, the tiny dots will dissolve to disappear and therefore the “X” looks lighter than background.Shown as the �gure：

If the plate is overdeveloped, the tiny dots will be attacked and start to disappear and therefore the “X” will look lighter than the background.

Shown on lift：

Please ensure developing time and temperature is correct if this occurs. The “X” will be harder to recognize under proper processing conditions. It may also indicate that the bath is too strong due to over replenishment when Arto R is used. Please con�rm replenishment rate is correct and conductivity of the bath is not increasing. If processing and replenishment is correct, then you may want to consider the exposure may be too high.（See 2.2.1）

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2.1.2 INSUFFICIENT DEVELOPINGIf developing time or temperature is insu�cient, some coating will remain in the non-image area among the tiny dots, the “X” will look darker visually than the background. It indicates developing is not enough.

Shown right:

Please ensure development time and temperature is correct. Also, con�rm replenishment rates are correct and developer conductivity is not more than 8 points below starting conductivity. Sometimes when the result you expect does not appear and, if processing and replenishment are correct, then you may want to consider the exposure may be too low.（See 2.2.2）

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2.2 EXPOSURE CONRTOLThe exposure energy will a�ect the reproduction of the small dots, both positive and negative. This can also be a�ected by incorrect focus values. These factors a�ect the plate more when the dot size is smaller. If process settings are con�rmed to be correct, you can assess exposure energy with this control zone.

2.2.1 OVER-EXPOSUREIf the exposure energy is too high, the tiny dots will be lost after developing even if the process settings are perfect.

Shown lift

It is hard to �x this problem merely by adjusting process settings. We can con�rm the laser is higher than we expect, if the processor is con�rmed to be set correctly and the chemistry is con�rmed not to be too aggressive due to over replenishment. If so, some adjustment of the exposure may be necessary until it is hard to see the “X”. Please refer to the Product Reference Manual for recommended exposure settings.

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2.2.2 INSUFFICIENT EXPOSUREWhen the exposure energy is not high enough the coating will not be properly processed and will remain on the plate among the tiny dots

Shown lift:

Even when the processing has been con�rmed to be correct and the chemistry conductivity has not dropped more than 8 points from starting conductivity, the control strip may look like the above example:

Due to a possible laser head quality issue, insu�cient exposure, improper focus settings or a dirty lens, we may see more coating than we expect in the background of the plates. Higher exposure energy, a lens cleaning or con�rmation of exposure and focus settings is likely needed. It should not be easy to identify the “X”.

2.3 NOTEDuring production, it is suggested that the “X” should be a little bit lighter than background to compensate for �uctuations in laser power, and processing conditions. This ensures the widest amount of latitude for all variables.

If the “X” in the �rst to third patch is invisible and visible in forth and �fth patch in the upper part with naked eye, the plate quality is stable and secure. The lower part is just the opposite.

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3FINE LINESThis part includes two groups of �ne lines. Each group contains vertical and horizontal lines distributed evenly, but have di�erent thickness: one is 1pixels, the other is 2pixels. The vertical lines are distributed in the top left and bottom right while horizontal lines in the top right and bottom left. Usually, we can tell the color di�erence between vertical lines area and horizontal lines area. If the vertical lines are thicker than horizontal lines after exposure, the vertical lines area is lighter than horizontal lines area and vice versa. The smaller the color di�erences between the two, the better the exposure condition.

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4CONCENTRIC CIRCLES

Shown right:The concentric circles group has two parts of positive and negative lines. Every ten circles share one thickness and the value is 1pixel, 2pixel, 3pixel and 4pixels from center to edge. The accuracy, continuity of the positive/negative circles indicates the plate-setters reproduction capability in �ne lines.

During production, plate should meet the requirements below:1) Fine reproduction of the inside ten circles. 2) The circle is continual and even;3) The positive parts have same thickness with negative.

The plate quality is stable and secure with the three requirements.

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5CONCENTRIC BOX

This control unit is mainly applied to assess exposure condition. It is made up of positive/negative �ne lines in di�erent thickness.

The thickness is increased every two lines in pixels and is as follows from the outside in: 20, 15, 10, 5, 4, 3, 2, 1.

Ideally, pairs of even, smooth positive/negative lines will have the same thickness with clear outline. If the positive line is thinner than negative, please decrease the exposure energy, otherwise, increase the exposure energy.

During production, the plate should meet the requirements below:1) The most internal two lines are clear;2) Fine lines are continual and even;3) The positive are the same thickness as the negative lines.

The plate quality is stable and secure with the three requirements.

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HALF TONE SCALE6

Shown Above:

In this control unit, the top part is vector scale without RIP so considered as Un-Calibrated. The bottom is processed by the RIP and is considered Calibrated.

6.1 VECTOR SCALEAll the patches in this group are not processed by RIP and these patches will represent un-calibrated imaging. The measurement of these patches will indicate the dot reproduction based on exposure, processing and plate capability. Deviation may indicate the need for plate-setter calibration and or improper process conditions.

6.2 RIP SCALEThe patches in this group are processed by the RIP and will represent any tonal curves applied to the plate. The RIP will apply calibration curves to the dots therefore these patches can be used to check the proper calibration curve is applied.

6.3 COMPARISON BETWEEN VECTOR AND RIP SCALEWe expect the dot value measured by dot reading equipment is equivalent to the objective value set by calibration curve. The error should be within ±1%. Please adjust your plate production settings if the values are not correct.

The dot reproduction can be identi�ed by RIP scale. The dot area is used to modify the calibration curve in order to get excellent dot reproduction and correct calibration curve.

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7The scale is used to monitor the output quality of Xingraphics positive thermal CTP plate. The �le format is PDF. Please add it to the job template to be imaged on each plate.

Usually, the scale is put to the center of edge in the distance of 15mm.Or somewhere out of image are.

The scale has 24 editions. Please use the below chart as reference to match the scale to your production:

There are two resolutions: 2400 dpi and 2540 dpi. Each resolution contains multiple editions shown as below:

NOTE IN USE

Screening methods Screening Line/um

AM-SQ 133 150 175 200 230 260 280

FM FM-10μm FM-15μm FM-20μm

Spekta Spekta 350 Spekta 650

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8 COPYRIGHT CLARIFY

Copyright ownership belongs to Xingraphics Ltd. This document involves proprietary information of Xingraphics. No unit and or person is allowed to use and reveal this document and picture, chart, data involved without written permission from Xingraphics.

The Xingraphics created and released this scale and reserves all rights. No unit and or person is allowed to copy part or all of the content of the scale for commercial purpose without written permission from Xingraphics.

This document will be updated regularly due to product upgrade and or any other reasons. This document should only be considered as advice. All the information and suggestions should not be considered as any form of guarantee unless some form of contract is signed in advance.

Edition：Xingraphics_DigiControl V3.5

Release Date: Jan 8th, 2012

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