diff --git a/dist/bundle.js b/dist/bundle.js
index d761be5..f044832 100644
--- a/dist/bundle.js
+++ b/dist/bundle.js
@@ -1,6 +1,6 @@
 
 /*
- *  lena.js - 0.3.1
+ *  lena.js - 0.5.0
  *  Library for image processing <https://github.com/davidsonfellipe/lena-js/>
  *
  *  Made by Davidson Fellipe.
@@ -21,6 +21,49 @@ const invert = function (pixels) {
   return pixels
 };
 
+const contrast = function (pixels, amount) {
+  const level = Math.pow((amount + 100) / 100, 2);
+
+  let data = pixels.data;
+  let r;
+  let g;
+  let b;
+
+  for (let i = 0; i < data.length; i += 4) {
+    r = data[i];
+    g = data[i + 1];
+    b = data[i + 2];
+
+    r = r / 255;
+    r -= 0.5;
+    r *= level;
+    r += 0.5;
+    r *= 255;
+
+    g = g / 255;
+    g -= 0.5;
+    g *= level;
+    g += 0.5;
+    g *= 255;
+
+    b = b / 255;
+    b -= 0.5;
+    b *= level;
+    b += 0.5;
+    b *= 255;
+
+    r = r < 0 ? 0 : r > 255 ? 255 : r;
+    g = g < 0 ? 0 : g > 255 ? 255 : g;
+    b = b < 0 ? 0 : b > 255 ? 255 : b;
+
+    data[i] = r;
+    data[i + 1] = g;
+    data[i + 2] = b;
+  }
+
+  return pixels
+};
+
 const mirror = function (pixels) {
   let tmp = [];
   const width = pixels.width * 4;
@@ -111,7 +154,7 @@ const brightness = function (pixels, amount = 0) {
   return pixels
 };
 
-const sepia = function (pixels) {
+const sepia = function (pixels, amount = 100) {
   for (let i = 0; i < pixels.data.length; i += 4) {
     let r = pixels.data[i],
       g = pixels.data[i + 1],
@@ -151,16 +194,15 @@ const saturation = function (pixels) {
   return pixels
 };
 
-const thresholding = function (pixels, args) {
+const thresholding = function (pixels, amount = 128) {
   for (let i = 0; i < pixels.data.length; i += 4) {
     let r = pixels.data[i],
       g = pixels.data[i + 1],
       b = pixels.data[i + 2];
 
     let v = 0.2126 * r + 0.7152 * g + 0.0722 * b;
-    let thr = args || 128;
 
-    pixels.data[i] = pixels.data[i + 1] = pixels.data[i + 2] = v > thr ? 255 : 0;
+    pixels.data[i] = pixels.data[i + 1] = pixels.data[i + 2] = v > amount ? 255 : 0;
   }
 
   return pixels
@@ -494,6 +536,7 @@ exports.bigGaussian = bigGaussian;
 exports.blue = blue;
 exports.brightness = brightness;
 exports.canny = canny;
+exports.contrast = contrast;
 exports.filterImage = filterImage;
 exports.gaussian = gaussian;
 exports.getImage = getImage;
diff --git a/dist/bundle.min.js b/dist/bundle.min.js
index 05c25ab..f44c76a 100644
--- a/dist/bundle.min.js
+++ b/dist/bundle.min.js
@@ -1 +1 @@
-var LenaJS=function(t){"use strict";const a=function(t){return t<0?0:t>255?255:t},e=function(t,a){for(let e=0;e<t.data.length;e+=4){let n=.2126*t.data[e]+.7152*t.data[e+1]+.0722*t.data[e+2],r=a||128;t.data[e]=t.data[e+1]=t.data[e+2]=n>r?255:0}return t},n=function(t,a){let e=Math.round(Math.sqrt(a.length)),n=Math.floor(e/2),r=t.data,d=t.width,o=t.height,l=document.createElement("canvas").getContext("2d").createImageData(d,o);for(let t=0;t<o;t++)for(let i=0;i<d;i++){let u=4*(t*d+i),h=0,c=0,f=0;for(let l=0;l<e;l++)for(let u=0;u<e;u++){let g=t+l-n,s=i+u-n;if(g>=0&&g<o&&s>=0&&s<d){let t=4*(g*d+s),n=a[l*e+u];h+=r[t]*n,c+=r[t+1]*n,f+=r[t+2]*n}}l.data[u]=h,l.data[u+1]=c,l.data[u+2]=f,l.data[u+3]=255}return l},r=function(t){return n(t,[0,-1,0,-1,4,-1,0,-1,0])},d=function(t){return t=n(t,[1/4,0,-1/4,.5,0,-.5,1/4,0,-1/4])},o=function(t){return t=n(t,[1/4,.5,1/4,0,0,0,-1/4,-.5,-1/4])},l=function(t){return n(t,[2/159,4/159,5/159,4/159,2/159,4/159,9/159,12/159,9/159,4/159,5/159,12/159,15/159,12/159,5/159,4/159,9/159,12/159,9/159,4/159,2/159,4/159,5/159,4/159,2/159])},i=function(t,a){t.width=a.width,t.height=a.height;t.getContext("2d").putImageData(a,0,0)},u=function(t){const a=document.createElement("canvas");a.width=t.width,a.height=t.height;const e=a.getContext("2d");return e.drawImage(t,0,0),e.getImageData(0,0,t.width,t.height)};return t.bigGaussian=l,t.blue=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=0,a[t+1]=0;return t},t.brightness=function(t,e=0){let{data:n}=t;const r=Math.floor(e/100*255);for(let t=0;t<n.length;t+=4)n[t]=a(n[t]+r),n[t+1]=a(n[t+1]+r),n[t+2]=a(n[t+2]+r);return t},t.canny=function(t){t=l(t);const a=function(t,a){let e=t.data,n=t.width,r=t.height,d=a.data,o=document.createElement("canvas").getContext("2d").createImageData(n,r),l=new Array(e.length).fill(0);for(let t=0;t<r;t++)for(let a=0;a<n;a++){let r=4*(t*n+a);o.data[r]=Math.sqrt(Math.pow(e[r],2)+Math.pow(d[r],2)),o.data[r+1]=Math.sqrt(Math.pow(e[r+1],2)+Math.pow(d[r+1],2)),o.data[r+2]=Math.sqrt(Math.pow(e[r+2],2)+Math.pow(d[r+2],2)),o.data[r+3]=255,l[r]=Math.atan2(d[r],e[r]),l[r+1]=Math.atan2(d[r+1],e[r+1]),l[r+2]=Math.atan2(d[r+2],e[r+2]),l[r+3]=255}return{magnitude:o,direction:l}}(o(t),d(t));return t=function(t,a){let e=Math.round(Math.sqrt(25)),n=Math.floor(e/2),r=t.data,d=t.width,o=t.height,l=document.createElement("canvas").getContext("2d").createImageData(d,o);for(let t=0;t<o;t++)for(let i=0;i<d;i++){let u=4*(t*d+i),h=r[u],c=r[u+1],f=r[u+2];for(let l=0;l<e;l++)for(let g=0;g<e;g++){let e=t+l-n,s=i+g-n;if(e>=0&&e<o&&s>=0&&s<d){let n=4*(e*d+s),o=Math.atan2(e-t,s-i);h=r[n]*Math.abs(Math.cos(a[u]-o))>h?0:h,c=r[n+1]*Math.abs(Math.cos(a[u+1]-o))>c?0:c,f=r[n+2]*Math.abs(Math.cos(a[u+2]-o))>f?0:f}}l.data[u]=2*h,l.data[u+1]=2*c,l.data[u+2]=2*f,l.data[u+3]=255}return l}(r(t),a.direction),e(t,8)},t.filterImage=function(t,a,e,n=0){let r=[u(e),n];return i(t,a.apply(null,r))},t.gaussian=function(t){return n(t,[1/16,2/16,1/16,2/16,.25,2/16,1/16,2/16,1/16])},t.getImage=u,t.grayscale=function(t){for(let a=0;a<t.data.length;a+=4){let e=t.data[a],n=t.data[a+1],r=t.data[a+2];t.data[a]=t.data[a+1]=t.data[a+2]=.2126*e+.7152*n+.0722*r}return t},t.green=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=0,a[t+2]=0;return t},t.highpass=function(t){return n(t,[-1,-1,-1,-1,8,-1,-1,-1,-1])},t.histogram=function(t){const a=this.getImage(t),e=new Array(257).join("0").split("");let n={r:e.map(Number),g:e.map(Number),b:e.map(Number)};for(let t=0;t<a.data.length;t+=4)n.r[a.data[t]]++,n.g[a.data[t+1]]++,n.b[a.data[t+2]]++;return n},t.invert=function(t){for(let a=0;a<t.data.length;a+=4)t.data[a]=255-t.data[a],t.data[a+1]=255-t.data[a+1],t.data[a+2]=255-t.data[a+2];return t},t.laplacian=r,t.lowpass3=function(t){const a=1/9;return n(t,[a,a,a,a,a,a,a,a,a])},t.lowpass5=function(t){const a=.04;return n(t,[a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a])},t.mirror=function(t){let a=[];const e=4*t.width;for(let n=0;n<t.height;n++){let r=n*e,d=t.width/2;for(let n=0;n<d;n++){let d=4*n,o=d+r,l=e-d-4+r;a[0]=t.data[o],a[1]=t.data[o+1],a[2]=t.data[o+2],a[3]=t.data[o+3],t.data[o]=t.data[l],t.data[o+1]=t.data[l+1],t.data[o+2]=t.data[l+2],t.data[o+3]=t.data[l+3],t.data[l]=a[0],t.data[l+1]=a[1],t.data[l+2]=a[2],t.data[l+3]=a[3]}}return t},t.prewittHorizontal=function(t){return n(t,[1/3,1/3,1/3,0,0,0,-1/3,-1/3,-1/3])},t.prewittVertical=function(t){return n(t,[-1/3,0,1/3,-1/3,0,1/3,-1/3,0,1/3])},t.printCanvas=i,t.red=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=a[t],a[t+1]=0,a[t+2]=0;return t},t.redrawCanvas=function(t,a){let e=t.getContext("2d");return e=[e.getImageData(0,0,t.width,t.height)],i(t,a.apply(null,e))},t.roberts=function(t){return n(t,[0,0,0,1,-1,0,0,0,0])},t.saturation=function(t){for(let a=0;a<t.data.length;a+=4)t.data[a]=2.31366*t.data[a]+-1.15596*t.data[a+1]+-.1558*t.data[a+2],t.data[a+1]=-.58634*t.data[a]+1.7440399999999998*t.data[a+1]+-.1558*t.data[a+2],t.data[a+2]=-.58634*t.data[a]+-1.15596*t.data[a+1]+(2.9-.1558)*t.data[a+2];return t},t.sepia=function(t){for(let a=0;a<t.data.length;a+=4){let e=t.data[a],n=t.data[a+1],r=t.data[a+2];t.data[a]=t.data[a+1]=t.data[a+2]=.3*e+.59*n+.11*r,t.data[a]+=40,t.data[a+1]+=20,t.data[a+2]-=20}return t},t.sharpen=function(t){return n(t,[0,-.2,0,-.2,1.8,-.2,0,-.2,0])},t.sobelHorizontal=o,t.sobelVertical=d,t.thresholding=e,t}({});
+var LenaJS=function(t){"use strict";const a=function(t){return t<0?0:t>255?255:t},e=function(t,a=128){for(let e=0;e<t.data.length;e+=4){let n=.2126*t.data[e]+.7152*t.data[e+1]+.0722*t.data[e+2];t.data[e]=t.data[e+1]=t.data[e+2]=n>a?255:0}return t},n=function(t,a){let e=Math.round(Math.sqrt(a.length)),n=Math.floor(e/2),r=t.data,d=t.width,o=t.height,l=document.createElement("canvas").getContext("2d").createImageData(d,o);for(let t=0;t<o;t++)for(let i=0;i<d;i++){let u=4*(t*d+i),h=0,c=0,f=0;for(let l=0;l<e;l++)for(let u=0;u<e;u++){let g=t+l-n,s=i+u-n;if(g>=0&&g<o&&s>=0&&s<d){let t=4*(g*d+s),n=a[l*e+u];h+=r[t]*n,c+=r[t+1]*n,f+=r[t+2]*n}}l.data[u]=h,l.data[u+1]=c,l.data[u+2]=f,l.data[u+3]=255}return l},r=function(t){return n(t,[0,-1,0,-1,4,-1,0,-1,0])},d=function(t){return t=n(t,[1/4,0,-1/4,.5,0,-.5,1/4,0,-1/4])},o=function(t){return t=n(t,[1/4,.5,1/4,0,0,0,-1/4,-.5,-1/4])},l=function(t){return n(t,[2/159,4/159,5/159,4/159,2/159,4/159,9/159,12/159,9/159,4/159,5/159,12/159,15/159,12/159,5/159,4/159,9/159,12/159,9/159,4/159,2/159,4/159,5/159,4/159,2/159])},i=function(t,a){t.width=a.width,t.height=a.height;t.getContext("2d").putImageData(a,0,0)},u=function(t){const a=document.createElement("canvas");a.width=t.width,a.height=t.height;const e=a.getContext("2d");return e.drawImage(t,0,0),e.getImageData(0,0,t.width,t.height)};return t.bigGaussian=l,t.blue=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=0,a[t+1]=0;return t},t.brightness=function(t,e=0){let{data:n}=t;const r=Math.floor(e/100*255);for(let t=0;t<n.length;t+=4)n[t]=a(n[t]+r),n[t+1]=a(n[t+1]+r),n[t+2]=a(n[t+2]+r);return t},t.canny=function(t){t=l(t);const a=function(t,a){let e=t.data,n=t.width,r=t.height,d=a.data,o=document.createElement("canvas").getContext("2d").createImageData(n,r),l=new Array(e.length).fill(0);for(let t=0;t<r;t++)for(let a=0;a<n;a++){let r=4*(t*n+a);o.data[r]=Math.sqrt(Math.pow(e[r],2)+Math.pow(d[r],2)),o.data[r+1]=Math.sqrt(Math.pow(e[r+1],2)+Math.pow(d[r+1],2)),o.data[r+2]=Math.sqrt(Math.pow(e[r+2],2)+Math.pow(d[r+2],2)),o.data[r+3]=255,l[r]=Math.atan2(d[r],e[r]),l[r+1]=Math.atan2(d[r+1],e[r+1]),l[r+2]=Math.atan2(d[r+2],e[r+2]),l[r+3]=255}return{magnitude:o,direction:l}}(o(t),d(t));return t=function(t,a){let e=Math.round(Math.sqrt(25)),n=Math.floor(e/2),r=t.data,d=t.width,o=t.height,l=document.createElement("canvas").getContext("2d").createImageData(d,o);for(let t=0;t<o;t++)for(let i=0;i<d;i++){let u=4*(t*d+i),h=r[u],c=r[u+1],f=r[u+2];for(let l=0;l<e;l++)for(let g=0;g<e;g++){let e=t+l-n,s=i+g-n;if(e>=0&&e<o&&s>=0&&s<d){let n=4*(e*d+s),o=Math.atan2(e-t,s-i);h=r[n]*Math.abs(Math.cos(a[u]-o))>h?0:h,c=r[n+1]*Math.abs(Math.cos(a[u+1]-o))>c?0:c,f=r[n+2]*Math.abs(Math.cos(a[u+2]-o))>f?0:f}}l.data[u]=2*h,l.data[u+1]=2*c,l.data[u+2]=2*f,l.data[u+3]=255}return l}(r(t),a.direction),e(t,8)},t.contrast=function(t,a){const e=Math.pow((a+100)/100,2);let n,r,d,o=t.data;for(let t=0;t<o.length;t+=4)n=o[t],r=o[t+1],d=o[t+2],n/=255,n-=.5,n*=e,n+=.5,n*=255,r/=255,r-=.5,r*=e,r+=.5,r*=255,d/=255,d-=.5,d*=e,d+=.5,d*=255,n=n<0?0:n>255?255:n,r=r<0?0:r>255?255:r,d=d<0?0:d>255?255:d,o[t]=n,o[t+1]=r,o[t+2]=d;return t},t.filterImage=function(t,a,e,n=0){let r=[u(e),n];return i(t,a.apply(null,r))},t.gaussian=function(t){return n(t,[1/16,2/16,1/16,2/16,.25,2/16,1/16,2/16,1/16])},t.getImage=u,t.grayscale=function(t){for(let a=0;a<t.data.length;a+=4){let e=t.data[a],n=t.data[a+1],r=t.data[a+2];t.data[a]=t.data[a+1]=t.data[a+2]=.2126*e+.7152*n+.0722*r}return t},t.green=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=0,a[t+2]=0;return t},t.highpass=function(t){return n(t,[-1,-1,-1,-1,8,-1,-1,-1,-1])},t.histogram=function(t){const a=this.getImage(t),e=new Array(257).join("0").split("");let n={r:e.map(Number),g:e.map(Number),b:e.map(Number)};for(let t=0;t<a.data.length;t+=4)n.r[a.data[t]]++,n.g[a.data[t+1]]++,n.b[a.data[t+2]]++;return n},t.invert=function(t){for(let a=0;a<t.data.length;a+=4)t.data[a]=255-t.data[a],t.data[a+1]=255-t.data[a+1],t.data[a+2]=255-t.data[a+2];return t},t.laplacian=r,t.lowpass3=function(t){const a=1/9;return n(t,[a,a,a,a,a,a,a,a,a])},t.lowpass5=function(t){const a=.04;return n(t,[a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a])},t.mirror=function(t){let a=[];const e=4*t.width;for(let n=0;n<t.height;n++){let r=n*e,d=t.width/2;for(let n=0;n<d;n++){let d=4*n,o=d+r,l=e-d-4+r;a[0]=t.data[o],a[1]=t.data[o+1],a[2]=t.data[o+2],a[3]=t.data[o+3],t.data[o]=t.data[l],t.data[o+1]=t.data[l+1],t.data[o+2]=t.data[l+2],t.data[o+3]=t.data[l+3],t.data[l]=a[0],t.data[l+1]=a[1],t.data[l+2]=a[2],t.data[l+3]=a[3]}}return t},t.prewittHorizontal=function(t){return n(t,[1/3,1/3,1/3,0,0,0,-1/3,-1/3,-1/3])},t.prewittVertical=function(t){return n(t,[-1/3,0,1/3,-1/3,0,1/3,-1/3,0,1/3])},t.printCanvas=i,t.red=function(t){let a=t.data;for(let t=0;t<a.length;t+=4)a[t]=a[t],a[t+1]=0,a[t+2]=0;return t},t.redrawCanvas=function(t,a){let e=t.getContext("2d");return e=[e.getImageData(0,0,t.width,t.height)],i(t,a.apply(null,e))},t.roberts=function(t){return n(t,[0,0,0,1,-1,0,0,0,0])},t.saturation=function(t){for(let a=0;a<t.data.length;a+=4)t.data[a]=2.31366*t.data[a]+-1.15596*t.data[a+1]+-.1558*t.data[a+2],t.data[a+1]=-.58634*t.data[a]+1.7440399999999998*t.data[a+1]+-.1558*t.data[a+2],t.data[a+2]=-.58634*t.data[a]+-1.15596*t.data[a+1]+(2.9-.1558)*t.data[a+2];return t},t.sepia=function(t,a=100){for(let a=0;a<t.data.length;a+=4){let e=t.data[a],n=t.data[a+1],r=t.data[a+2];t.data[a]=t.data[a+1]=t.data[a+2]=.3*e+.59*n+.11*r,t.data[a]+=40,t.data[a+1]+=20,t.data[a+2]-=20}return t},t.sharpen=function(t){return n(t,[0,-.2,0,-.2,1.8,-.2,0,-.2,0])},t.sobelHorizontal=o,t.sobelVertical=d,t.thresholding=e,t}({});
diff --git a/docs/all-filters.html b/docs/all-filters.html
index 85556c9..c57ee5a 100644
--- a/docs/all-filters.html
+++ b/docs/all-filters.html
@@ -10,7 +10,7 @@
   <body>
     <div id="result" class="board">
       <div class="box">
-        <img id="image" src="assets/img/coffee.jpg" width="300" height="400" />
+        <img id="image" src="assets/img/sf.png" width="300" height="400" />
       </div>
     </div>
 
@@ -21,6 +21,12 @@
       var result = document.getElementById('result')
 
       var filters = [
+        { name: 'contrast', amount: 100 },
+        { name: 'contrast', amount: 50 },
+        { name: 'contrast', amount: 0 },
+        { name: 'contrast', amount: -50 },
+        { name: 'contrast', amount: -100 },
+        { name: 'grayscale', amount: 0 },
         { name: 'brightness', amount: -50 },
         { name: 'brightness', amount: 0 },
         { name: 'brightness', amount: 50 },
@@ -31,7 +37,6 @@
         { name: 'invert', amount: 0 },
         { name: 'mirror', amount: 0 },
         { name: 'thresholding', amount: 0 },
-        { name: 'grayscale', amount: 0 },
         { name: 'sepia', amount: 0 },
         { name: 'saturation', amount: 0 },
         { name: 'roberts', amount: 0 },
diff --git a/docs/assets/img/camera.png b/docs/assets/img/camera.png
new file mode 100644
index 0000000..48b2abe
Binary files /dev/null and b/docs/assets/img/camera.png differ
diff --git a/docs/assets/img/sf.png b/docs/assets/img/sf.png
new file mode 100644
index 0000000..62c81c4
Binary files /dev/null and b/docs/assets/img/sf.png differ
diff --git a/lib/filters/contrast.js b/lib/filters/contrast.js
new file mode 100644
index 0000000..986e479
--- /dev/null
+++ b/lib/filters/contrast.js
@@ -0,0 +1,44 @@
+const contrast = function (pixels, amount) {
+  const level = Math.pow((amount + 100) / 100, 2)
+
+  let data = pixels.data
+  let r
+  let g
+  let b
+
+  for (let i = 0; i < data.length; i += 4) {
+    r = data[i]
+    g = data[i + 1]
+    b = data[i + 2]
+
+    r = r / 255
+    r -= 0.5
+    r *= level
+    r += 0.5
+    r *= 255
+
+    g = g / 255
+    g -= 0.5
+    g *= level
+    g += 0.5
+    g *= 255
+
+    b = b / 255
+    b -= 0.5
+    b *= level
+    b += 0.5
+    b *= 255
+
+    r = r < 0 ? 0 : r > 255 ? 255 : r
+    g = g < 0 ? 0 : g > 255 ? 255 : g
+    b = b < 0 ? 0 : b > 255 ? 255 : b
+
+    data[i] = r
+    data[i + 1] = g
+    data[i + 2] = b
+  }
+
+  return pixels
+}
+
+export default contrast
diff --git a/lib/index.js b/lib/index.js
index 3e80b32..7d9f070 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,4 +1,5 @@
 export { default as invert } from './filters/invert'
+export { default as contrast } from './filters/contrast'
 export { default as mirror } from './filters/mirror'
 
 // RGB filters
diff --git a/package.json b/package.json
index 8cd36b3..2321add 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "lena.js",
-  "version": "0.4.2",
+  "version": "0.5.0",
   "description": "Library for image processing",
   "homepage": "https://github.com/davidsonfellipe/lena-js/",
   "author": {