Getting a good laser file

Which file for which software

DTO Studio saves the picture with its size and DPI inside, so your laser software opens it at its real size. Pick the file by the program you burn with:

• xTool Creative Space (XCS): the Greyscale PNG (the default): pick Jarvis or Stucki in XCS and set its DPI to the file's. A Pre-dithered (1-bit) PNG is already dotted: don't let XCS dither it again.
• LightBurn: the same Greyscale PNG, image mode Jarvis or Stucki at the file's DPI. A Pre-dithered (1-bit) PNG is already dotted: don't let LightBurn dither it again.
• Logos, lettering and cutting: SVG (shapes). Every shape is closed, at its real size in mm. Use Fill to engrave it or Line to cut round it. For a cut line round the subject, pick Outline SVG under More file types in Save, in Guided or Advanced (it needs a photo with its background removed; send a Styles result there first).
• Most other software (LaserGRBL, RDWorks, EZCAD, Glowforge): PNG; JPG only if the program refuses PNG; 1-bit or 24-bit BMP for programs that read BMP.

DPI (dots per inch)

DPI (dots per inch) is how close together the laser's dots and lines are. 254 DPI puts them 0.1 mm apart (10 lines per mm, 100 lines per cm). Higher is finer, but only up to the width of your laser's mark: dots closer than about half the mark run together and the picture goes dark.

Starting points: diode and CO2 lasers 254-318 DPI on wood, leather and slate; fiber and UV lasers 600 DPI and up on metal and glass. You pick the DPI in Studio (Crop & size); a material never changes it.

Set the same number in your laser software (LightBurn: Line interval or DPI; xTool Creative Space: lines per cm). The file name carries it too.

Dot patterns (dithering)

A laser burns or doesn't burn: it has no grey. Dithering turns greys into a pattern of tiny dots, more dots for darker greys. By default Studio saves your edited picture as a greyscale PNG and your laser software dithers it: pick Jarvis or Stucki there, at the file's DPI. Close-up shows how the dots will look. A Pre-dithered (1-bit) PNG with Studio's own dots is optional.

• Smoothest (Jarvis): the default for photos.
• Smooth and a touch sharper (Stucki).
• Lighter and crisper (Atkinson): good on light woods, loses some shadow detail.
• The classic, a little grainier (Floyd–Steinberg).
• Even random dots, no worm-like lines (blue noise).
• Halftone (newspaper dots) and stipple (hand-drawn dots) are looks of their own; no dots = a grey file your laser software dithers.

Dithering in your laser software

Open the Greyscale PNG in your laser software and let it make the dots: Jarvis or Stucki, at the file's DPI (xTool Creative Space: the same lines per cm). Don't resize it there, or the dots no longer match the DPI.

Only if you chose the optional Pre-dithered (1-bit) PNG: it is already dotted, so tell your software not to dither it again (LightBurn calls that Pass-Through or Threshold).

Materials: when the picture is inverted or mirrored

Picking a material sets its look (tone, invert, mirror); the DPI stays yours. The rule is simple: where the laser's mark comes out darker than the surface (wood, leather, paper, white tile sprayed with toner) the picture stays as it is; where the mark comes out lighter (slate, black tile, black granite, glass, anodized aluminum, powder-coated tumblers) the picture is inverted, so the light marks make the picture.

Glass and clear acrylic engraved from the back are mirrored, so the picture reads the right way from the front. You can switch invert and mirror yourself on step 4 (Edit & material).

Starting power and speed for each material are in the table below; the Starting settings card on step 5 (Save) gives them for your exact laser and power.

Starting power and speed, and test grids

The settings card on step 5 (Save) gives a published starting point for your laser type, power and material: power %, speed (mm/s and mm/min) and passes, with where the numbers come from. It is a starting point, not tested on your machine: lasers of the same wattage differ, and so do woods.

Run the power & speed test grid (Advanced › Laser) on a scrap of the same material: it burns a small square at each power and speed. Tap the best one and Studio saves it as your tested setting for that laser and material; the settings card then uses it.

Tick "Also save the laser settings (.txt)" to save these numbers as a text file next to your picture.

Words you'll see

Dot pattern (dithering)

Dot pattern: the picture is turned into tiny burn / no-burn dots, so greys become more or fewer dots.

Jarvis, Stucki, Atkinson, Floyd–Steinberg

Names of dot patterns. Jarvis is the smoothest and the default; Stucki is a touch sharper; Atkinson lighter; Floyd–Steinberg a little grainier.

Line interval

How far apart the laser's lines are, in mm: the same thing as DPI said the other way round (0.1 mm = 254 DPI).

Invert

Invert: swaps black and white, for materials where the laser marks light (slate, black tile, glass).

Mirror

Mirror: flips left-right, for engraving from the back of glass or acrylic.

1-bit PNG

1-bit PNG: every pixel is either burn or no-burn, nothing in between. Tiny files, burned exactly as saved.

DPI / lines per cm

DPI = dots per inch: how close together the laser's dots or lines are. 254 DPI = 10 lines per mm. Lines per cm: the same as DPI in metric (xTool Creative Space asks for it). 254 DPI = 100 lines per cm.

Mark width

Mark width: how wide one burned line is on the material (the laser's spot). Dots closer than that run together.

Optical watts

Optical watts: the light power that reaches the material. Diode lasers are sold by it (a "40 W" diode is often 5-10 W optical).

Norton method

Norton method: white tile sprayed with toner or paint, engraved, then wiped; the burned toner stays dark.

Recipe

Recipe: the list of steps Studio applies to your photo, in order. Change, reorder or switch off any step.