photos intro powerpt

Laser Engraving PhotosLaser Engraving Photos

who am i

40 years in the awards and engraving business

Manufacturers Rep since 1988

Has been selling lasers since 1991

Have been using CorelDraw since 1991

Featured writer for the Engravers Journal

Constantly calling on Engravers and Trophy shops

who am i

My lines include

Full line of Trophy Supplies such as resins, glass, plaques, and acrylics

Custom Castings

Full Line of solid wood and custom manufacturing

Full line of engraving equipment, sublimation and engraving supplies

Who Am I

• My email is • mike@engrave.ca

• My website is• www.engrave.ca

our lesson purpose

My purpose today is to make you a better photograph engraver using your laser machine

I will take you through my 4 rules for successfully lasering photos

The second part of this seminar will look at the steps needed for each material that we want to engrave.

why 3 hours

Some people asked me why I need 3 hours.

I need 3 hours because there are a number of factors and techniques you need to consider when you are lasering photographs.

please have patience

I have spent years developing the techniques we discuss here

A number of them I have developed myself

These techniques are new because everyone wants to think that they can tell people to just buy software and it works

One Stop Photo Software

A lot of people talk about buying photo processing software for the laser as if it is the only consideration when it comes to laser engraving photos. Although photo manipulation is important it is not the only one techinque that we need to know

There are a number of factors and techniques that will determine whether you are successful or not at processing a photo for your laser

Spending $250 does not give you a free pass to guarantee a perfect photo

4 Factors For a Good Photo

• Rated in order

A Good Quality Photo

Proper Power and Speeds for your laser

Know your material

Software

A Good Quality Photo

Good Quality Photo

There are a number of ways to look at what constitutes a good photo

Is the lighting good?

Is there good detail?

Is there good focus?

Most importantly does the file suffer from too much compression (artifacting)?

Good Lighting

Bad Lighting Good Lighting

Good Lighting

To Much Red ColourRed colour cast

Good Normal Colour

Good Lighting

This Image Comes Up to

This Image Comes Up Just Right

Good Detail

To Far Better Detail

is our image all there

GoodBad if you arelooking to

laser the tractor

is The Focus Good

Bad Good

is the image to compressed

Bad Good

JPEG Compression

One of the big problems that we face is that most photos that we are given now a days by our customers have been taken on a Digital camera.

The problem with digital camera’s is you just never know the quality of photo you are going to get in terms of the compression that was used when the photo was made. The higher the compression the worse the image will be for lasering

Highly compressed photos can greatly decrease the chances of achieving a good photographic representation on your laser

JPEG Compression

For this reason it is very important that we analyze a photo when we get it so that we can check for compression issues that would effect the quality of our photo

If the photo you receive has a high degree of compression this should raise a red flag in terms of being cautious as to the results you will get from lasering the image.

it is a good idea to zoom in on an image

Zoom in on the image to check the quality

This photo is of very good quality

CorelDraw

it is a good idea to zoom in on an image

Zoom in on the image to

check the quality This photo is not very good

quality

Here is how it lasers

The image has been lasered

on black anodized

aluminum. The detail is not

there because of all the

compression applied

Same Image just less compression

Here is the same image less compression

Same Image just less compression

The image has been lasered

on black anodized

aluminum. The detail is a lot

better as there is a lot less

compression happening

Here is Another issue with Compression

Zoom in on the image to check the quality. On the left you see how there are chunks or blotches in the yellow circles. You can see what happens to the image in the Unsharp Mask. The blotches a

very pronounced

Too much compression causes blotchiness in our image

When there is a lot of

compression blockiness

when we go to sharpen we end up with

large “blocks” which is no good for our

Or is the image just no good to begin with

OriginalConverted

Proper Power and speed

Proper Power Laser Settings

Probably one of the areas where most laser users miss is making sure their laser settings are set properly for the material that they are lasering on. I call this maximizing your powers and speeds for a material

One of the first steps we should do when we get our laser is to create the proper power and speed settings for each one of the materials we are going to work with - and I mean all of them. Save them all.

Do not believe what your laser manufacturer tells you is the proper power and speed

Here Are Some Manufacturer’s Presets

I would be at least 10 to 15 % lower

Notice this is for marble not granite

300 DPI 400 DPI 600 DPI

Speed to Power

As you can see the laser settings that are listed by the manufacturer are not the ones that I would use.

To be fair - with all the materials that are available it is hard to have proper powers. For example when we say engraving plastic there are so many variations which one would you list is hard to decide.

Also everyone is different. For example I may like a deeper engraving than someone else. Thus my power and speed will be different from someone else. So as you can see it is very hard to have so called factory presets.

So for this reason it is very important that you test you materials so that you get the best combination of power and speed

And to be more precise we should have a proper power and speed for the resolution you want to run whether is be 300, 400, 500 or 600 DPI.

Sample file done on anodized aluminum

The Manufacturers setting was 100 s 40 power. There is suppose to be an emblem in the background.

100 Speed 30 Power 600 DPI. There is to much power being used on this material

100 Speed 20 Power 600 DPI. The detail is coming up

100 Speed 12 Power 600 DPI. So much better detail

100 Speed 12 Power 600 DPI - Perfect Image

Original Power30 Power

Final Power12 power

Here is another example

This is a difference of 3 percent in power. Same speed

MissingLine

BolderFont

Less Power

More Power

Here are 3 vector and 3 raster lines engraved at different powers and the same

Notice how the vectors line increase

in width as the power increases

Notice how the raster line increase

in width as the power increases

Here is one more example

Here is another example of too much power - black granite

how can we explain this over burning

So the question for us here is to understand what is going on in terms of explaining why this over burning is happening. What is going on is the higher the power we use (which could also be slower speed) the bigger the laser dot becomes.

The bigger the laser dot that is created by the laser the more material that is removed by the laser through this larger dot.

Dot Gain

Thus as our power increases or our speed decreases our laser spot size increases. This is because our power increases. If our power goes down or our speed goes up our laser spot or dot becomes smaller

When it comes to explaining this rule I call this dot gain - which is the same term used in the printing industry. The more ink you use the “bolder” the image becomes

What is going on?

This is a very important rule that must be considered when we are working with any material on our laser. If our dot gain becomes to much we can obliterate our image.

I remember the first time I tried to laser a photo onto black granite. I used 100 power and 100 speed on a 75 watt laser. All I got was a big white rectangle. I had so much power there was no image left

Dot Gain - the shape of a lasered dot

The Yellow Circleis the Original laser

beam spot size

The area outside of the yellow circle

is the so - called “gain” that

happens when the heat spreads out

Another laser spot

The Yellow Circleis the Original laser

beam spot size

The area outside of the yellow circle

is the so - called “gain” that

happens when the heat spreads out

Dot Gain creates the over burn

So the way that dot gain works is the higher the power you produce with your laser the bigger the gain becomes and thus the spot size becomes bigger

For example if your creates a laser spot size of .005 when it hits your material that is the size of the laser spot. As more heat is absorbed by the material our spot size could grow to a size of 0.025 or 5 times the original size. If the power is too much it can “interfere” with neighbouring spots or dots.

This is why images become “thicker” due to over burn.

The bigger the size of the spot the more overlap we get between the laser dots. Combine this with higher resolutions and we can create a lot of dots in a 1 square inch size.

This is why images become “thicker” due to over burn. Over burn will quickly obliterate our image

Thus it is critical that we get our laser powers perfect

Remember power can be expressed in a combination of laser power, motion speed and printed resolution (such as 600 DPI)

Normal Laser Spots

Let us assume that the diagram below is a rendition of a series of laser dots or spots laid

down at a proper power and speed. In this case we have our spots touching

To much power

If we use to much power our spots become bigger. Our offset will remain the same. Thus we now have spots running into each other

little To power

If we use to little power our spots become smaller. Our offset will remain the same. Thus we now have large spaces between our spots. This can mean some parts of our image may

be gone due to not enough power by the laser.

printing Resolution

Laser printing resolution is the amount of laser dots or spots that are laid down in a 1 inch box. The acronym DPI stands for dots per inch.

The higher the DPI theoretically the better the quality we will get. This is not always right but for the most part it is.

400 DPI means 400 dots horizontally and 400 dots vertically. 600 DPI means 600 dots horizontally and 600 dots vertically.

printing Resolution

The more dots that we print the more overlap we will have.

For this reason increasing the resolution will increase the amount of laser burning in an inch box. This is like dot gain but the spot sizes remain the same. What changes is the overlap.

The higher the resolution the longer it takes to engrave as we have more lines

Never use 1200 DPI for photos. It is not necessary

printing Resolution

400 DPI

600 DPI

Here are two representations of two different printed resolutions. The red box is representing a 1 inch box.

The spots are the same for each. The 600 DI has more lines than the 400 DPI. Thus there is more overlap and

thus more burn by the laser in the inch box.

now that we have a better understanding of what is

resolution and dot gain let us look at how to create proper

power and speed settings

Two Ways to create proper settings

1.One is to create a black box and adjust your power and speed settings as you laser

2.The second is to use colour mapping to run multiple powers or speeds at the same time

There are two ways to create proper laser tests

using the black box

All though I tease everyone when I go through this step to try and get them to think it is some super secret technique it is very easy and most machines will support this technique

The First Method is to Use the Black Box

using the black box

The black box method is easy because all we are doing is sending an image (black box) over to the laser with a preset power and speed

Once the job starts we start adjusting our power or speed from our laser machine.

As we are adjusting our power or speed we are monitoring the burn to see if it is satisfactory

using the black box

The big question is what is a proper power and speed?

Some of it really depends on you and what you consider a proper power. For example if we are engraving wood the proper power will be what depth you want to laser at.

To me pretty is in the eye of the beholder. What you think is right may not be right in my eyes.

Golden Rule

The Proper Power and Speed typically is the least amount of power that we can get away with but still get a good quality looking image.

This may seem a little foreign considering no one really explains how the manufacturer derives the power and speeds that they suggest.

Just remember the more power you use the less detail you can create. Considering we want detail than using less power is preferable over too much.

First create a black box in Coreldraw

Our Black Box

Our Box is 2 “ wide and 3” tallThe box an be any height just choose something that will run for a minute or two

Set up the printer driver

Set Up For Anodized Aluminum on a 60 WattNotice How Low the Power is

Printing Resolution

Only Raster

Raster Speed

No Vector Setup

adjust the power on your laser machine

Speed Button allows us to select the speed and adjust itThe Power button allows us to select the Power and adjust itThe Up and Down arrows in the red box allow us to change the value

Adjust the power or speed as the machine moves

for vectors we need to keep sending different power and speed jobs

insert vector video

Here is our box engraved

Notice how the rectangle skews

inwards where the low power burn is

Our Sample Material was Brushed Gold

Engraving Plastic

Save the settings in the print driver

using colour mapping

Sometimes when we need to test a material adjusting the power as we go does not work that well. One example is with Thermark. I can adjust the power or the speed but I can not see my adjustment till I wash off the Thermark on steel or tile. It is not very practical to laser, wash off, clean, respray. This goes the same for glass that we mask.

For this reason it is better to run a number of settings all at once. We do this with colour mapping.

The Second Method is to Use Colour Mapping

Sometimes when we need to test a material adjusting the power as we go does not work that well. One example is with Thermark. I can adjust the power or the speed but I can

not see my adjustment till I wash off the Thermark on steel or tile. It is not very

practical to laser, wash off, clean, respray. This goes the same for glass that we mask.For this reason it is better to run a number

of settings all at once. We do this with colour mapping.

Engrave by colourtesting File

Here are a couple of

testing files where I use

colour mapping. Each

colour represents a

different setting

Engrave by colourtesting File

Here are a couple of test patterns that I

created on ceramic tile.

Notice how the Thermark

spray adheres at different

setting.

Help File

Go to this link to see a more

through discussion on this topic. You will be able to down load the

test file.

http://www.engrave.ca/archives/5348

know what type of photograph you are working

the difference between black and white and grayscale

Black and White Image Grayscale ImageOur grayscale image looks better than the error diffusion image

Error Diffusion Image Continuous Tone Image

know your material

Know Your MaterialFine or coarse

Ok here is the number one rule of being successful with lasering photos. The way we process a photo is dependent on the type of material we are lasering on.

If we look further into this statement we see that we actually come out with two types of material. We have what I like to call fine and coarse material. Depending on the material type will determine the way I process my photo.

Grayscale looks better on fine material

Error Diffusion Image Grayscale Image

Our grayscale image looks better than the error diffusion image

Good Best

Error Diffusion looks better on coarse material

Error Diffusion Image Grayscale Image

Our error diffusion image looks better than the grayscale image

GoodBest

Fine Material

Fine material is the first of our two types of materials that we classify our material into

What is a “Fine Material”?

Characteristics of fine material

Large Contrast (white or black)

No Grain (engraving plastic)

Able to hold a good dot

Able to hold a small dot

Typically requires lower power

Types of fine materials

Laserable Plastic

Anodized Aluminum

Laserable Aluminum

Black Blass Plated Steel

Leather

Acrylic

AlumaMark

Examples of Fine materials

Anodized Aluminum

leather

Engraving plastic

black brass plated steel

laser aluminum

gold aluma mark

silver aluma mark

Coarse material

Coarse Material - coarse material can be classified as any material that has a lot of grain in it and or it can not hold a small lasered dot. For example oak would be a very coarse material because it has a lot of grain in it - actually a very bad grain when it comes to lasering. For that matter all wood is coarse. For me the coarser the material the less detail we will leave in our image - more on that later.

characteristics of coarse materials

Low Contrast

Lots of Grain

Able to hold or create a large not small dot

Typically requires higher power

The photo looks better when we remove the background - use Cutout Image

types of materials

Marble

Thermark Materials

Mirror

Corian

Fabric

Examples of coarse materials

corian

marble

thermark /cermark

Mirror

Material chart

Fine Materials Coarse Material

Anodized Aluminum Granite

AlumaMark Thermark Materials

Engraving Plastic Glass

Mirrored Acrylic All Wood Products

Acrylic Corian

Laser It Mirrors

All Laser Engraving Metals Marble

Why Do we have fine and coarse materials

The reason we need to place our materials into these two different categories is that we will process our photos differently depending on whether the product is a fine material or a coarse material

Thus the product we use will dictate how we process a photo.

Processing a photo

We will now go through the steps on how to process a photo.

Note that the initial steps are the same for each photo except there is an extra step for coarse materials

processing a photo for lasering fine material

Here is my image

All images need to converted to grayscale first

Fine material stepsanodized aluminum

With the image selected go to BITMAPS | MODE | GRAYSCALE

What does a proper grayscale image look like

This is what a proper grayscale image should look like. Notice that it has a good level of variation in light

to dark

Image converted to gray on the left is to dark. The image on the right is lightened up with the contrast

enhancement tool

To access the contrast enhancement tool go to EFFECTS |ADJUST | CONTRAST

ENHANCEMENT

Our image is to dark. The histogram shows this

Original Preview

The secret to adjusting a photo is to isolate the

“flash” areas of the face by making them a more solid

Our next step is to open the Unsharp Mask command. Go to BITMAPS | SHARPEN | UNSHARP MASK

Here is the command window for the Unsharp Mask

Our Image Sharpened

Why Do We Need to Sharpen Our Image?

All photos that we get whether they are scanned in our from a digital camera have a certain amount of “fuzziness” applied to them. This is a product of the process of digitizing a photo. This fuzziness cause an issue where your eye finds it very hard to distinguish changes in colours.

To get rid of this fuzziness use a technique called Unsharp Mask. This technique “sharpens” up the image by tricking your eye to see a more pronounced separation between colours

We need to Invert the image as we are placing the image on a black surface material. Go to EFFECTS|

TRANSFORM|INVERT

Here is our image inverted and ready to send to the laser

Here is my finished image lasered on anodized aluminum

Here is a close up of the grayscale photo. Notice the detail in the bracelet

Here is a close up of the black and white photo. Notice the loss of detail

Here is another finished image lasered on

anodized aluminum

let us now look at the steps to use to get the image ready to engrave on a coarse material

With the image selected go to BITMAPS | MODE | GRAYSCALE

COARSE MATERIAL STEPSWOOD PRODUCTS

Image converted to gray. It is too dark so it needs to be lightened up with the contrast

enhancement tool

To access the contrast enhancement tool go to EFFECTS |ADJUST | CONTRAST

ENHANCEMENT

Our image is to dark. The histogram shows this

Our Image Has Been Adjusted With The Contrast Enhancement

coarse material stepsWood products

Our Image Sharpened

Our next step is too convert our image to black. To do this go to BITMAPS|MODE|BLACK AND WHITE

When we are in the command window your conversion method is Jarvis. You can adjust the Intensity slider if you want to change

the effect

Our Image Converted to Black and White

Our Image Finished

in my experience fine materials make better photos than coarse materials. they hold more detail

and thus can create a better looking photo. thus if you have the

choice to choose your material choose a fine material

although converting to greyscale in coreldraw is easy to do there is

better control if we use photopaint. this is especially true if the image

has what is known as a colour cast. this is where one colour of the image - say red - has become

dominant do to proper exposure or lighting

in Corel photopaint we can easily correct this using the convert to

greyscale command. this is easy to do and be very quick to fix colour

issues in a photo

New Technique greyscale conversion via photopaint

Here is my test image. Notice the bias in the red colour in the photo. This will cause issues when I convert to grey if done in

CorelDraw

Send the photo to photopaint from coreldraw

You can open up the image in PhotoPaint or CorelDraw. Here I have opened the file in CorelDraw and I can open it in PhotoPaint by right clicking on the image and select “Edit Bitmap”. I will be

able to save the changes back to the file in CorelDraw

Here is our image in photopaint

Here is our image in PhotoPaint

Access the convert to grayscale command

To access the Grayscale command we need to go to IMAGE|CONVERT TO GRAYSCALE

Access the convert to grayscale command

When we open up the command you have te two window view. There are also sliders that relate to colour. Each slider allows

to add (black) or subtract (white)

adjust the red in the photo

When we open up the command you have te two window view. There are also sliders that relate to colour. Each slider allows to add (black) or subtract (white). I have moved the red slider

right.

Before After

Adjust the yellow in the photo

Here is our image adjusted for red (Before). The After photo shows my yellow adjustment. These two adjustments give me a very good tonality to the photo as it has reduced the red and

yellow

Before After

Adjust the green in the photo

Nothing happens to the image when I adjust the Green.

Adjust the cyan in the photo

Nothing happens to the image when I adjust the Cyan. For that matter nothing happens we we adjust the Blues or the

Magentas

What About Cropping

HERE IS A PHOTO THAT NEEDS TO CROPPED

OUR PHOTO HAS BEEN CROPPED

Resampling a photo

One of the important steps that people fail to utilize is to adjust their photo so that it it has a proper resolution. The proper screen resolution for a laser machine is typically any where from about 100 PPI 150 PPI. The proper resolution though is based on the fact that the photograph must be size as. Thus if you are lasering a photo that’s 5 inches the screen resolution should be 100 PPI to 150 PPI. For this reason it is important that we note the size and resolution of our image before we laser our photo.

Resampling a photo

The status bar indicates that the resolution of this image is 180 dpi by 180 dpi

Resampling a photo

The property bar indicates that the photo is 3.43 inches wide by 2.405 inches tall

Resampling a photo

If I make my image 8 inches wide then you notice that my screen resolution has dropped to 77 dpi by 77 dpi. Thus I will need to increase my resolution of my image. I will use

the resample command.

Resampling a photo

To open the resample command go to BITMAPS|RESAMPLE

Resampling a photo

Here is the resample command opened up. Notice that I have unchecked the anti-alias button. Our image size is

783 kB

Resampling a photo

I have increased the resolution from 77 dpi 150 dpi. Notice the file size increased four times - 2.90 MB

Resampling a photoRules

When you resize an image you change its resolution if you increase the size of resolution goes down if you decrease the size and resolution goes up

When you want to change the size of the image and keep its resolution the same use the resample command. If the resolution is not right use the resample command to fix it

Make sure you know the size of the photo that you want to laser. This is very important

What About Resolution?

resolution some important points for photos

If you are lasering a photograph as a grayscale image your best printing resolution is 500 or 600 DPI. As we decease the resolution your image will take on the look of the a screen. The lower the resolution the more the screen effect will appear

Grayscale Image Printing

600 DPI Grayscale Image

No Graininess or “Screen” effect

Starting to see a “Screen” effect

Now we see a strong “Screen” effect

all 3 resolutions

If you are lasering a photograph as a black and white image (error diffusion) you can run any resolution from 300 up and the look will be the same.

Even lower resolutions of 150 and 200 are good

Black and White Image Printing

This photo shows minimal quality issues between the lower resolutions. The

quality is there we are just losing some of the amount of dots that we can laser

with a lower resolution

This photo shows minimal quality issues between the lower resolutions. The

quality is there we are just losing some of the amount of dots that we can laser

with a lower resolution

When it comes to grayscale images it is better to run at 500 or 600 DPI

When it comes to black and white images a resolution of 300 or 400 should be fine - unless you are looking for more power because of the increase in dots

If you run at different resolutions you will need to adjust your powers or speed to compensate for more or fewer dots

cutout lab

Cutout lab

On Coarse Materials It is Best to Remove the Background

Cutout lab

The Background Interferes With the Image

Cutout lab

Our Background is Removed

Cutout lab

Our Image Looks Good

Dodge and burn tool

dodge and burn

We have lost the black shirt and hat

dodge and burn

The Dodge Tool Brings Them Back

photos on wood

photos on glass

Samples of glass

Samples of glass - grayscale

Samples of glass

Samples of glass - grayscale

Samples of glass

samples of glass

using a premask is the only way to do photo on glass

Our Glass is small fractures

mask your material

using a premask is the only way to do photo on glass

Thermark

thermark on tiles

granite

Granite

Granite - painted and not

Granite - painted

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