Prepping Photos-Wood

Introduction

This Course is designed for you to take the necessary steps to prep your photos so that they will engrave on WOOD. It is designed to use generic terminology and options that are in MOST artwork software.

NOTE: Adobe users. These features are in PHOTOSHOP NOT ILLUSTRATOR. I will give generic terms for you to refer to, however I am doing it in Corel Draw. You will need to refer to your manual on your artwork software to find where these options are in your software.

Step By Step

Import a Photograph

Open CorelDraw in a new file and Import the photo of your choice.

Here is the photo i used if you want to download and compare: beg-prep-wood-intro-1.jpg

At this time, go into your software and change the color to GRAYSCALE:

You should get this:

Resample

This is a crucial part of the process. Most people think by grabbing the corner of the picture, it makes it bigger and adds more pixels. DON’T EVER DO THIS.

• Image Resizing: Changing the size the image will print without changing the number of pixels in the image.
• Image Resampling: Changing the number of pixels in the image.

You always want to Re Sample. Also once you have finished prepping your photo, you CANNOT resize or resample. It will ruin the picture.

Ive changed the size of the image, and increased the resolution from 300 to 600. Some systems only allow you to change it from 250,500,1000 DPI. If this is the case for you, make it 500.

Tone Curve

What is Tone Curve? A lot of people might be confused, or they might be intimidated by how a Tone Curve works, but it’s really quite simple. The Tone Curve is a powerful tool that can be used to make advanced tonal adjustments on your image.

We use Tone Curve a LITTLE at a time when processing images for engraving.

Gamma Correction

What is Gamma Correction?

It lets you accentuate detail in low contrast areas without affecting shadows or highlights. In a nutshell. Its going to make your engrave look really light. THAT’S OK. YOU WANT THAT!

Change your Gamma Value to 3.5

See how the picture is light, but is still detailed? It’s perfect.

Unsharp Mask (Sharpen)

Although it sounds counter-intuitive, you use the “Unsharp Mask” to sharpen an image. “Sharpening” means to increase the level of contrast between the colors of neighboring pixels. When using the Unsharp Mask, you can adjust sliders to change the level of sharpening, including the amount percentage, radius and threshold. The Amount determines how much you sharpen, with a higher value creating a stronger effect; Radius determines the how wide the edges around your selected area sharpen; and Threshold determines the color value between the adjacent pixels that you want to sharpen.

Make your percentage 500, your radius 20 and your threshold 6

 

That is the “POP” that the laser needs to give it that really fine detail. Now, Go to the same drop down and hit sharpen

 

Make your Edge Level 100, Threshold 70, and check preserve colors

Change To Black & White 1 Bit (Epilog Only)

Now is the time (at least on Corel) where we change it to Black and White 1 bit so the laser can read it properly. There are different ways of changing a photo for different lasers. THIS STEP IS FOR EPILOG ONLY. Go to the next step for all others!

Click on Black and White, 1 Bit.

 

Make your conversion method halftone

Angle at 0

100 Lines Per Inch

Screen Type: Line

 

You should get this:

 

Change To Black & White 1 Bit (RDWorks/Chinese Lasers)

Send It To The Laser

If you have an Epilog, send the image to the Laser. In your printer driver, choose 600DPI, Jarvis Dithering, and for a 50 watt laser, use 40% Speed, 100% Power

If you need to send it to a third party software, you need to export it out. Make sure your DPI is 600, you choose 1 bit and check the dithered box

 

In your laser, make sure your scan gap is 1/600*25.4 This is the conversion method to mm.

Conclusion

So there are a few things you can do to fine tune a picture.

1. You can increase or decrease the Tone Curve, but only in LITTLE STEPS. One square at a time
2. You can make your Gamma a little less, again a tiny bit at a time
3. Finally you can adjust the Unsharp mask to fine tune as well
4. In the laser settings, if you think it will burn too hot, that’s ok. Turn up the speed, and lower the power. Remember, you can always make it darker. You cant Un Burn something.
5. If its a little dark when you are done, take 600 Grit sandpaper to it so you can buff out the overburn, Lightly!!

Now one last thought. Does this mean EVERY picture you do will come out perfect. If you pick great photos, and stick to the process, you should have really nice results, however it all is about how well the picture is balanced out.