Photo engraving using GridPhoto

Contents: Creation of milling data in GridPhoto. Import Photo. Scaling. Filter. Mirror + rotate. Line gridding Gridding. DitherPicture Dithering. Hatching. Waves + circles Milling data view Milling data graphics. Milling data > layer. Milling data e xport. Navigator. Work specification: milling data from photo.

Creation of milling data in GridPhoto. Grid Photo is a convenient solution for 2D photo engraving. Grey scale images are converted from programs using a few Mouse clicks into high quality milling data for almost all 3 or 4 axis machine tools. In GridPhoto, grey scale images are processed and converted into dotted or linear milling data. The photos should be available as grey scale images with 256 colours (exception .JPG). The imported images can be edited, scaled, filtered, mirrored and very rapidly converted into milling data. With milling there results a gridded image which resembles a photo, for example in a daily newspaper The light/dark variations (grey scales) in the photo are created through dots or lines with appropriate intensity or density. Using Milling data graphics you can monitor the calculated milling data and, as required, repeat the calculation with modified settings as often as you wish. Grid Photo has available various grid, dither and hatching processes for the creation of optimum milling data. In the g rid process grey scales are created through dots with varying diameter and the same separations (3D milling data). The d ither process creates grey scales through dots with the same diameter and variable separations (2Dmilling data). With the hatching process the grey scales are represented through 2D hatching lines in adjustable directions and separations. Help on the functions can be obtained with the activated navigator using <F9>, in the menu also using [?] and clicking-on the function.
Import photo.
Import a grey scale image and adjust dimensions (measurements). The program imports Bitmap files (256 Grey scales, 8Bitgrey scales, 1Byte/Pixel) in the following formats:
BMP | Windows Bitmap with 256 gray shades.
GIF | CompuServ Bitmap with 256 gray shades. The GIF -format contains no information on size or resolution. The image dimensions must be adjusted manually after import.
PCX | Paintbrush Bitmap with 256 gray shades.
JPG, JPEG | JPEG Bitmap with 256 gray shades, 8Bit colours and 24Bit colours. JPG images with 24Bit colours are converted into a gray shade image on import.
TIF, TIFF | The TIFF - import is qualified for 8bit (1 byte/pixel) and 16bit (2byte/pixel) unpacked grayscale pictures. With 16bit TIF, reliefs with higher resolution can be saved or opened. Optional is a fee required TIF - import/export extension obtainable for more picture formats and packed formats.
Before calculation of the milling path a photo should be processed into a photostyler (e.g. Corel PHOTO-PAINT) and saved as grey scale image (8Bit/Pixel - not in colour, exception .JPG). Images in the .JPG - format can also be saved as colour images (24Bit). On import these are converted into grey scale images. Gridded photos (e.g. from periodicals) have a very rough surface and should as far as possible be avoided or reworked in a suitable photostyler. Gridded images can also be improved using approximate fine/strong. Height - width ratio (Input in mm):
Proportional : |
YES: | All axes modified proportionally the same.
No: | The axes are input individually.
Dimension X/Y/Z [mm] | Input of the measurements in mm.
After import the picture size must be set for milling. Good results at manageable milling time can be reached with X / Y - dimensions of 100 - 200 mm. The Z - depth should be at about 0.5mm (0.4 - 1.0mm). For 'Line gridding' the Z - depth determines the milling data resolution also dependent on the tool data. Small milling depths result in finer, large depths result in coarse milling data. Example picture dimensions 119mm x 153mm
Z - depth 0,7mm | Z - depth 1,5mm | Z - depth 3,0mm
Scaling.
Adjust a relief in size and resolution.
Scaling %: | Adjust measurements in X/Y/Z (input in %). With Proportional = YES all axes are the same, with No the axes are entered individually.
Dimensions XYZ: | Height-Width ratio (input in mm). With Proportional = YES all axes are the same, with No the axes are entered individually.
Reduction %: | Enlarge image in X/Y remove dots and with this reduce resolution and amount of data.
Levels: | Grey tone grading, coarsen image in Z.
Double resolution: | Double resolution of the overall image in X/Y. The position and enlargement remain unchanged.
Filter.
Revise/smooth the photo. Suitable filters are, for example, approximate.
Error pixels: | Regional filter. The dot, which deviates from all its neighbouring values by more than the specified value, is approximated (smoothed).
Outliers: | Regional Filter. Delete large deviations to the neighbouring dots.
Approximate/ approximate heavily: | The relief is smoothed. The approximating can, as required, be repeated several times.
Smooth: | The relief resolution is doubled and the image is, at the same time, lightly smoothed. This filter gives significantly higher amounts of data and should therefore be used only for coarse images. Images with too high a resolution can be reduced again using 'scale . reduce (e.g.: [%] = 50)'
Radius filter: | Smooth the relief, all edges are rounded off.
Correction filter 1: | Smooth the relief, all edges are rounded off on one side.
Correction filter 2: | Fill holes (e.g. after STL import).
Mirror + rotate.
In the case that it has still not taken place the image can be rotated or mirrored in all axes. Mirror complete image in X, Y, Z and rotate by +/-90°.
Mirror X/Y/Z: | Mirror image in X, Y or Z.
Countershape XZ: | Simultaneous mirroring for a countershape in X and Z direction.
Rotate +90°/-90°: | Rotate image by +90° (counter-clockwise) or -90° (clockwise).
Line gridding.
Using line gridding grey scale images are milled using a conical tool in 3D lines. The tool, depending on image brightness sinks to different depths in the material and thus creates the photo in the workpiece. Light areas of the image result in small milling depths and, through the tool cone, small line widths. Dark areas of the image, on the other hand, result in large milling depths and wide lines. With import of the photo the image is converted into a relief. The measurements X/Y are the dimensions of the photo (reliefs). These ca be adjusted using 'scaling'. The milling depth is determined by the relief depth (input/modification, for example using scaling . dimension Z). For the engraving of photos no large milling depths are necessary, usually a few 0.1 mm suffice. The normal procedure is the engraving of the image and subsequent covering (filling) of the cutter track using colour. With the employment of multi-layer material the thickness of the upper milling layer must be noted (set the safety height (Off) higher and incise slightly deeper). Display in upper window.
Measurement X/Y [mm]: | Measurements of the image and the engraved workpiece.
Max. milling depth Z [mm]: | Indication of the tool insertion depth in the material (relief depth).
Milling path separation: | The milling path separation (separation of the milling lines) is tool radius multiplied by the line separation (/100%) with max. depth. The milling path separation is heavily dependent on the tool angle TAn) and the relief depth. Smaller tool angles or smaller milling depths result in more milling data. The more lines which are milled the better effect the image has. But with this the milling time increases.
Line number: | Number of determined milling lines.
No. of layers: | Calculated number of layers. If the 'layer depth' is selected >= 'Max. Milling depth Z', then there is only one milling layer.
Inputs.
Tool #: |
Typical tool setting for 'Line gridding'.
Selection of a suitable milling tool. For milling, conical tools (with cone angle (CAn) >0°, e.g. 20..30°)are always to be employed. The cutter tip should be selected as small as possible (CuT <0.1 mm). For small cutter tips always pay attention to sufficient rpm.
Line separation [10..500%]: | The line separation is related to the tool radius with max. milling depth (100%). The milling path separation is determined by the line separation. A larger line separation results in a larger milling line separation and an image with a lighter effect. Recommended settings for photo engraving are 100% .. 300%. Reliefs (e.g. Lithophane for transmitted light) can be milled using the program. For this a tool with larger tip radius or spherical radius and smaller line separation (ca. 10..50%) is to be selected. With line gridding only a tool offset of the cutter tip is calculated. We therefore recommend the relief module or the program eMillRelief for correct relief production.
Angle [-90..+90°]: | Setting of the angle of the milling lines. 0° produces horizontal lines.
Procedures: | Milling method selection:
| Hatching: Simple lines without turnaround.
| Cross hatching: Simple lines without turnaround + 90° rotated crossings.
| Hatching meander: Lines in zigzag order.
| Cross hatching meander: Lines in zigzag order + 90° rotated crossings.
| Rectangle: Rectangles concentrically ordered.
| Circle: Circles concentrically ordered.
| Spiral: Elliptical spiral.
| Radial lines: Simple radial lines without turnaround.
| Radial lines meander: Radial lines in zigzag order.
| Spiral > rectangle: Elliptical spiral go over to rectangle form.
Layer depth [mm]: | Dependent on the Max. Milling Depth Z the image can be milled in one or more layers. If the layer depth is exceeded, the program creates several milling layers.
Contrast [-0.5..+0.5]: | With values >0 the image is higher-contrast (light and dark grey scales are reinforced). With values <0 are milled with less contrast.
Inverse [Y/N]: | YES: The brightness levels are inverted. Light areas are milled dark, dark areas are milled light.
Lines 100% | Cross-hatching 150%
Gridding.
Using gridding the grey scales in the image are created by dots of various diameter and the same separations. The variable dot diameters are created using a conical tool, which is sunk (inserted) appropriately deep into the material. Small dot diameters are achieved through small insertion, large dot diameters through strong insertion (3D milling data). Conical tools and a 3D machine tool are demanded for the grid process. Display in upper window.
Dimensions X/Y [mm]: | Dimensions of the image and of the workpiece.
Max. milling depth Z [mm]: | Indication of the greatest milling depth (for black dot) in the material. The max. milling depth results from the dot separation and the tool angle.
Number of dots X/Y/total number of dots: | Possible number of dots if all dots in the lines are milled. At 'white' points in the image no dots are milled. Please not the indication of the number of dots during the input. The milling time (ca. 1-4 dots/sec) can be estimated easily using the number of dots.
Inputs.
Tool tip radius [mm]: | Smaller dot separations and a greater total number of dots can be achieved using a small tip radius. The tip radius should be selected as small as possible (finest grid dot).
Tool angle[°]: | Conical tools are required for gridding. Convenient tool angles lie at 40..49°. Smaller tool angles increase the milling depth.
Safety height (SH) [mm]: | Safety clearance of the cutter tip to the surface of the material for withdrawn movements. The smaller the safety height is chosen the more dots can be milled at the same time.
Processes: | Milling processes for the image.
Vertical: | Each dot is milled vertically from the safety height into the material (long movements).
Inclined from Mat.: | The dots are milled into the material inclined along the tool angle. Up to the next dot an inclined movement takes place up to the material surface (short 3D movements).
Lines: | The individual milling depths are connected together by lines so that milled lines of different depth and thus different stroke widths result (short 3D movements).
Inclined from SH: | The dots are milled inclined along the tool angle into the material. Up to the next dot an inclined movement up to the safety height takes place (long 3D movements).
Dot separation [mm]: | Separation of the grid points. The dot separation must be selected at least 4 x Tool tip radius, otherwise no contrast is possible within the image. The greater the ratio Dot separation/ Tool tip radius is selected, the more contrast is possible in the milled image.
Density value: | A density value < 0 results in a lighter image after the engraving.
Example for dot grid. | Example for line grid.
DitherPicture
| Conversion of rastered b/w pictures to milling points. The pictures must be present in a purely 1bit - b/w - format. Gray shades or color picturesare not allowed for this conversion.
| Pictures with more than 1bit pro pixel (gray shaded or color) must be converted with a photostyler into b/w pictures. This conversion You receive e.g. using 'PhotoPaint'. Please select in PhotoPaint 'picture . convert into b/w (1bit)'. Here You have several methods for disposal. PhotoPaint converts colors in usable point structures. With DitherPicture the point structures are converted into milling points for Your machine.
Eingaben.
Tool #: |
Typical tool setting for 'DitherPicture'.
Selection of a suitable milling tool. For milling, conical tools (with cone angle (CAn) >0°, e.g. 20..30°)are always to be employed. The cutter tip should be selected as small as possible (CuT <0.1 mm). For small cutter tips always pay attention to sufficient rpm.
Procedure: | Milling procedure for the picture. Adjustable are horizontal and vertical processing.
Invers [Y/N]: | YES: The brightness levels are inverted. Light areas are milled dark, dark areas are milled light.
Milling data from DitherPicture.
Dithering.
New process from Ver. 7.022
The dither process creates the grey scales in the image through dots with the same diameter but variable separations (2D milling data). Cylindrical or conical tools can be employed for the dither process. A 2D (2.5D) machine tool suffices for the milling processing. The dither milling data can, in a wide range, be matched to the job definition. An image milled using the dither process is effective from a minimum viewing separation. A sufficiently large image should also be milled. The program offers 3 milling processes: Dither ing 9p, Dither ing 16p and Dither ing 25p. Dither ing 25p should be used for large area images only, Dither ing 9p is suitable for rather smaller images. To test a suitable milling image select Settings (see below) and Start. You can repeat the calculation using changed settings as often as you like. For a rapid graphic set the Milling data aspect to Milling point Through the relatively large-area dither dots the dimensions of the graphic cannot be adhered to exactly. The deviation of the milled image is visible in the graphic. Display in the upper window.
Dimensions X/Y [mm]: | Dimensions of the image and of the workpiece.
Max. milling depth Z [mm]: | Indication of the tool inserted (sunk) depth in the material.
Number of columns X / lines Y: | Possible number of the dither dots if all dots are milled in the lines. No dots are milled at 'white' points in the image, a dither dot consists, depending on the process, of several (up to 9, 16, 25) 2D dots.
Inputs.
Tool tip radius [mm]: | Smaller dot separations and a greater total dot number are achieved using a small tip radius. The tip radius should be selected as small as possible for a high image resolution.
Tool angle[°]: | Cylindrical [0°] and conical tools [>0°] are employed for dithering. Convenient tool angle lies at 10..20°.
S afety height (SH) [mm]: | Safety height of the cutter tip to the material surface for withdrawn movements. The smaller the safety height is selected the shorter is insertion (sink) movement and the more dots can be milled at the same time.
Inserted (sunk) depth [mm]: | Milling depth of the tool measured from the tool tip to the surface of the material.
Density [-0.5..+0.5]: | Change the milling dot density. With values <0 the dots are more dense, with values >0 are wider displaced.
Spread [0..1]: | Spread of the individual dots. With the setting 0 the dots are placed at regular intervals (best quality). Using larger settings the dots are dispersed. A spread results in a small reduction in quality. The image appears somewhat washed out/blurred.
Brightness [-0.5..+0.5]: | With values >0 the image is milled lighter, with values <0 milled darker.
C ontrast [-0.5..+0.5]: | With >0 the image is milled with higher contrast, with values <0 with less contrast.
Inverse [Y/N]: |
YES | The brightness level is inverted.
No | Brightness distribution as in the model.
Processes: | Dither milling processes for the image.
Dithering 9p: | For rather smaller images with reduced grey scale intensity. For 1 dither dot 0(white) .. 9(black) individual dots are milled (fine resolution).
Dithering 16p: | For medium-sized image sizes with sufficient grey scale intensity. For 1 dither dot 0(white) .. 16(black) individual dots are milled (medium resolution).
Dithering 25p: | For larger images with many grey scales. For 1 dither dot 0(white) .. 25(black) individual dots are milled (coarse resolution).
Comparison of the dither processes. From left to right 9p, 16p and 25p. Above spread 0, below spread 0,5.
|  | Same image as above but double dimensions and brightness + contrast respectively 0.1. Setting s. image. Milling data view setting Relief view.
Hatching.
Convert grey scale image into hatched image. For this the grey scale number is reduced and the individual level replaced by hatching so that a gridded image results. For an as high as possible contrast result a photo should be processed in a photostyler beforehand. Here, disruptive elements should be removed and a stronger contrast selected. For the hatching a tool must be determined whose tip is to be selected as fine as possible (Cutter tip [CuT] 0.05..0.1mm). The hatching separations are determined automatically using the cutter tips, the grey level and the following settings.
Hatching levels [1..32]: | A grey level image (256 levels) is reduced to 1..32 hatching levels. Sensible are 4..32 hatching levels.
Density [-20..100%]: | Change hatching density (line separation). The effect corresponds with the contrast setting. Values < 0 reduce the contrast, values > 0 raises the contrast.
Brightness [-20..100%]: | Change hatching separation for all hatching levels uniformly. The effect corresponds with a brightness setting.
Hatching contour separation [0..100%]: | Determines the safety separation of the milling tracks in the milling direction to the contour (track). With the selection Combine hatching lines = YES this value must be > 0 and lie at ca. 50% (>10% .. 70%).
Hatching angle [-2,-1.0..180°]: |
-2 | The hatching angle is automatically set for each layer with increasing value.
-1 | The hatching angle is automatically set for each layer with increasing value and alternatively displaced by ca.90°.
0..180 | The hatching angle is set for all angles at the specified value.
hatching directions [1..6]: |
1 | Hatching lines in set direction only.
2 | Hatching lines in set direction, displaced + 90°.
3 | Hatching lines in set direction displaced + 60° and 120°.
etc.
Join hatching lines [Y/N]: | YES: The hatching lines are joined together.
Add hatching contours [Y/N]: | Yes: S ave the hatching limits to the created paths.
Tool input for hatching. For the creation of milling data complete tool information is required. The tool data are entered in the tool list. The tool list can be reached with Tool Input.
Waves + circles
With RasterCut 'waves + circles' shade Pictures are milled in 3D milling lines for a conic tool. The tool dips in various depth into the material following the brightness and creates the photo into the workpiece. Bright picture areas takes place small milling depths and with the tool cone a small line width. Dark picture areas in comparison results large milling depths and wide lines. With the import the photo is converted into a 3D relief. The dimensions X/Y are the photo (Relief) dimension. These can be adopted with 'Scaling'. The milling depth is determined by the relief depth (input/change e.g. with 'Scaling . Measurement Z'). For photo engraving large milling depths are not necessary, some 0.1mm are mostly enough. The normal process is the picture engraving and fill the milling path with color. If You use multiple layer (color) material, please consider the thickness of the upper material layer (enlarge the safety height (Off) and dip in something deeper). Display in the window above
Dimension X / Y [mm]: | Dimension of the picture and the engraved work piece.
Max. milling depth Z [mm]: | Shows the milling depth (relief depth) in the material.
Path separation [mm]: | The shown amount is the minimal milling path separation for the selected tool. With max. milling depth (black) the milling paths will touch with another. The path separation is a strong depending with the tool angle (FWi) and the relief depth. Smaller tool angle or smaller milling depth takes place more milling lines. The picture will be clearer as more as lines are milled, but the milling time raises also.
Display in the window below
Input for 'sharp wave' .. 'B-spline wave'. | Input for 'circles left-top' .. 'circles right-bottom'.
Tool #: |
Typical tool setting for 'Waves + circles'.
Selection of the milling tool. For the line grid milling always a conic tool is needed (FWi > 0°, e.g. 20..30°). The tip radius should be selected as much as small (FrS <0.1 mm). For small tip radius please always mind for enough revolutions per minute.
Procedures: |
| Selection for the shape of 'waves' and 'circles'. Waves: Input 'sharp wave' .. 'B-spline wave'. The result for 'Q-spline wave' and 'B-spline wave' is nearly the same. A 'Q-spline wave' passes more equable. Circles: Input 'circles left-top' .. 'circles right-bottom' for the center location to the picture shapes.With 'corner distance' (see below) the center can be displaced to external or internal.
Angle [-90..+90°]: | Angle for the milling rows. 0° results horizontal rows. Angle is only applied for the waves procedures.
Line separation [0,1..1000mm]: | See 'Path separation' above. The 'Line separation' should not be smaller then the shown 'Path separation'.
Wave length [0,1..1000mm]: | Length of a wave respectively separation of the wave repeating. Input is only applied for the waves procedures.
Amplitude [0..1000%]: | Wave amplitude in % of the 'wave length'. For 'circle wave' the amplitude is limited to 100%. With amplitude = 0% straight lines are created. Input is only applied for the waves procedures.
X-offset [0..100%]: | Wave starting displacement in of the 'wave length'. Input is only applied for the waves procedures.
Corner distance [-9999..+9999mm]: | Corner separation for the circle centers. Input is only applied for the circles procedures.
Meander [Y/N]: | With 'Yes' the milling paths are produced in an meander, this means every second path is driven backward. With 'No' all milling paths start at their origin.
Cross-shaped [Y/N]: | With 'Yes' waves and circles are milled 2 times. The second way is shifted with 90°.
Layer depth [mm]: | Dependent to the 'Max. milling depth Z' the picture can be milled in 1 or more layer. If the 'Layer depth' is entered smaller than 'Max. milling depth Z' the program produces multiple milling layer.
Contrast [-0,5..+0,5]: | With settings >0 the picture will be rich in contrast, with settings <0 the picture contrast will be smaller. The picture will be shade off.
Invert [Y/N]: | Yes: The gray levels were inverted. Bright areas are milled dark, dark areas are milled bright..
Shaps of the selectable procedures, (angle always 0°)
Sharp wave | Trapezoid wave | Circle wave
Q-spline wave | B-spline wave | circles left-top
Example for milling data Picture dimension X=100mm x Y=100mm x Z=0,8mm
Q-spline wave, angle -45°, line separation 1.5mm, wave length 120mm, amplitude 80%, cross-shaped Yes. | circles left-top, corner distance 0mm, cross-shaped No..
Milling data view
| From the milling paths a relief (3D form) is calculated and drawn in grey scale image (slow display due to the high computing time).
Milling data graphics.
| Drawing of the milled image in plan view with filled cutter trace (cutter simulation).
Milling data > Layer.
Take over the milling data in a graphic layer.
| After 'Milling data > Layer' the characteristic data of the calculated milling data may be indicated. For this following select 'Layout . List layer cont.'. This function lists information such as cutting length and milling time (depending on the set of the tool feed rates).
Milling data export.
Following calculation, the milling paths can be exported in various formats.
Navigator.
| In the Navigator the most important program functions are summarised in the correct processing order. The Navigator leads you through the processing. Processing takes place from top to bottom. You can select the function marked in black. If a function is not to be selected then, using next you switch to the next operation. Using back you switch to the previous function.
Open (Import photo): | Import a grey scale image and adjust the dimensions (measurements).
F ilter: | Rework/smooth (finish) the image. Suitable filters are, for example, approximate.
Mirror+rotate: | In the case that it has still not taken place, the image can be rotated or mirrored in all axes.
Raster photo: |
Gridding. | With Gridding the grey scales are created in the image through dots with different diameters and the same separations.
Dithering. | The Dither processes create the grey scales in the image through dots with the same diameters and variable separations (2D milling data).
Hatching. | Convert grey scale image into hatched image. For this the grey scale number is reduced and the individual levels is replaced by hatching so that a gridded image results.
Milling data export: | Following calculation the milling paths can be exported in various formats.
End Navigator: | Program operation without Navigator. Now all menu functions are available. For operation please follow the program help [?] or <F9> and click-on the function.

Work specification: milling data from photo.
| Using GridPhoto grey scale images are converted into milling data for 3 or 4 axis machine tools. The photo must be available in a readable pixel format (BMP, PCX, GIF, JPG) with 256 grey scales. Photos in other formats must be converted into the required format beforehand using a standard photostyler (e.g. Corel Photo Paint). In the photostyler, delete unwanted areas of the image and cut the image into the desired dimensions. Convert colour images and images with other tones into greyscale images with 256 gradations (grey scales (8 Bit)). Alternatively, you can also save the image in .jpg format with 24 Bit colour depth.
Import photo. To work with GridPhoto the employment of the Navigator is recommended (it is active with first start). You open the image file using Import Photo. The program immediately shows you the input to the image scaling. Here you set the dimension of the milling data. For the example dimensions of X = 50 mm, Y = 54.4 mm are desired. For this, first put proportional to YES and change the dimension X to 50 mm. After clicking-on the next number all values are changed proportionally (the image format is retained). F ilter. The image is present in an unsatisfactory quality. The quality can be improved using the installed filters. Using approximate the image is smoothed and somewhat improved. Mirror + rotate. As required the image can here be rotated or mirrored. C alculate milling data. For this case the image is to be gridded using 3D dots. for this the function Gridding is selected (settings see picture). Export milling data. Before export, the milling paths should be viewed regularly using Milling data graphics. For these milling data a 3D milling machine with controlled X, Y and Z axes is required. Exported are the milling data using Export milling data and the selection of the desired export filter. In Export filter selection, select for example DIN/ISO and the export filter WinPC-NC / PC-NC. Note: For PC-NC the core image format for arcs (ABSOLUTE/relative) must be set the same in both programs (under Parameter). The approach position, with -9999.99, can be switched off for X and Y. In this case the working off starts with the 1st work position. Finished!